lisan_prosiding simposium kimia analisis malaysia ke-18, 2005

SSKKAAMM 1188

SIMPOSIUM KIMIA ANALISIS MALAYSIA KELAPAN BELAS

Sains Analisis Cemerlang Negara Terbilang

E-PROSIDING

12 – 14 September 2005 Hotel Hyatt Regency Johor Bahru, Johor

anjuran bersama

Jabatan Kimia, Fakulti Sains, Universiti Teknologi Malaysia dan

Persatuan Sains Analisis Malaysia (ANALIS)

dengan kerjasama

Institut Kimia Malaysia (Cawangan Selatan)

Prosiding Simposium Kimia Analisis Malaysia Ke-18, Johor Bahru

SESI KERTAS KERJA LISAN

1A Alam Sekitar I Pengerusi: Prof. Madya Dr. Salihan Siais (UPM) Bilik: Sri Mersing

1A-1 ANALISIS UNSUR DAN KERADIOAKTIFAN DALAM SAMPEL SEDIMEN TASIK CHINI, PAHANG DARUL MAKMURAMRAN AB.MAJID (UKM)

1A-2 TRACE ELEMENTS IN OREOCHROMIS NILOTICUS (RED TILAPIA) FROM FISH PONDZAHARAH AIYUB (UM)

1A-3 THE CHARACTERISTICS OF GEOCHEMISTRY AND SEDIMENTOLOGICAL IN PAKA RIVER SEDIMENT ONG MENG CHUAN (KUSTEM).

1A-4 PYROLYSIS AND LIQUEFACTION OF ACETONE AND MIXED ACETONE/TETRALIN PRE-SWELLED MUKAH BALINGIAN MALAYSIAN SUB-BITUMINOUS COAL – THE EFFECT ON COAL CONVERSION AND OIL YIELDMOHD FAUZI ABDULLAH (UiTM)

1A-5 KANDUNGAN LOGAM BERAT DAN RADIONUKLID TABII DALAM IKAN, AIR, TUMBUHAN DAN SEDIMEN DI BEKAS TASIK LOMBONGMUHAMAD SAMUDI YASIR (UKM)

1B Kimia Tak Organik dan Pemangkinan I

Pengerusi: Prof. Madya Dr. Razali Ismail (UTM) Bilik: Sri Pontian

1B-1 X-RAY CRYSTALLOGRAPHY AND BIOLOGICAL PROPERTIES OF INDOLE-AROMATICHYDRAZONE AND THEIR METAL COMPLEXES HAPIPAH MOHD ALI (UM)

1B-2 CHARACTERIZATION OF NOVEL ORGANOTIN(IV) COMPLEXES WITH O, N, O – DONOR LIGAND DERIVED FROM CARBOHYDRAZIDE: X-RAY CRYSTAL STRUCTURE OF [PH SN(H CBS)]2 2LIEW YEW ZION (UNIMAS)

1B-3 THE PREPARATION AND CHARACTERIZATION OF ISOMERIC SCHIFF BASES AND THEIR TRANSITION METAL COMPLEXES STRUCTURE-REACTIVITY RELATION FIONA HOW NI FOONG (UPM)

1B-4 STUDY ON BIMETALLIC NI/CO CATALYST DOPED WITH PRASEODYMIUM USING VARIOUS SUPPORT FOR CO / H METHANATION TOWARDS PURIFICATION OF NATURAL GAS

2 2

FARIDAH MOHD MARSIN (UTM) 1B-5 KAJIAN KRISTALOGRAFI SINAR-X BIS(N-(O-METILFENIL)-N’-(P-

METOKSIBENZOIL)-TIOUREA -κS)-DIIODOMERKURI(II) DAN BIS[µ-1-(2-PIRIDIL-κN)ETANONE-4-FENILTIOSEMIKARBAZONATO-κ2N1,S]BIS[IODOMERKURI(II)] MOHD SUKERI MOHD YUSOF (KUSTEM)

1C Teknik Pemisahan I

Pengerusi: Prof. Dr. Mohd. Marsin Sanagi (UTM) Bilik: Sri Muar

1C-1 MULTIRESIDUE ANALYSIS OF PESTICIDES IN FRUITS AND VEGETABLES USING SOLID PHASE EXTRACTION AND GAS

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SESI KERTAS KERJA LISAN CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR GUAN H. TAN (UM)

1C-2 SUBCRITICAL WATER EXTRACTION OF ESSENTIAL OIL FROM CORIANDER (CORIANDRUM SATIVUM L.) SEEDSNORASHIKIN SAIM (UiTM)

1C-3 PERKEMBANGAN SATU TEKNIK PENGEKSTRAKAN FASA PEPEJAL BAGI ANALISIS ASID HALOASETIK (HAAs) DALAM AIR MINUM MARINI AB. RAHMAN (UKM)

1C-4 ANALYSIS OF RESIDUAL TOLUENE IN FOOD PACKAGING MATERIALS USING HEADSPACE GAS CHROMATOGRAPHYLIM YING CHIN (UiTM)

1C-5 SYNTHESIS OF 3-O-SUCCINYL-BETULINIC ACID AS ANTI –CANCER AGENTS AGAINST HUMAN MYELOID LEUKAEMIA AND HUMAN T-4 LYMPHOBLASTOID CELLS LINE. MOHD. TAJUDIN MOHD. ALI (UiTM)

1D Organik/Bioteknologi I

Pengerusi: Prof. Madya Dr. Habsah Mohamad (KUSTEM) Bilik: Ballroom

1D-1 KEKABU SEED OIL EXTRACTION AND PUFA ISOLATION JUMAT SALIMON (UKM)

1D-2 TOXICITY AND ANTITERMITE ACTIVITIES OF THE ESSENTIAL OILS FROM PIPER SARMENTOSUMCHIENG TIONG CHIN (UNIMAS)

1D-3 MICROBIAL INFLUENCED CORROSION CAPABILITY OF SULFATE-REDUCING BACTERIA ISOLATED FROM THE MALAYSIAN SHIPYARD AND ENGINEERING HARBOURS, PASIR GUDANGFATHUL KARIM SAHRANI (UTM)

1D-4 KAJIAN PENGOPTIMUMAN TINDAK BALAS SAPONIFIKASI MINYAK KACANG SOYA HASNISA BINTI HASHIM (UKM)

1D-5 ENZYMATIC SCALE-UP PRODUCTION OF PALM OIL WAX ESTERS − OPTIMIZATION USING RESPONSE SURFACE METHODOLOGY KENG PEI SIN (UPM)

2A Alam Sekitar II

Pengerusi: Prof. Madya Dr. Ahmad Saat (UiTM) Bilik: Sri Mersing

2A-1 VOLATILE ORGANIC COMPOUNDS IN MALAYSIAN DRINKING WATER : IS IT AN ISSUE? MD. PAUZI ABDULLAH (UKM)

2A-2 REMOVAL OF HEAVY METAL IONS WITH ACID ACTIVATED CARBONS DERIVED FROM OIL PALM AND COCONUT SHELLS MOHAMMAD ADIL (UTM)

2A-3 KANDUNGAN TOLUENA DAN XILENA DALAM DEBU JALAN DI SEKITAR KUALA LUMPURMOHD ROZALI OTHMAN (UKM)

2A-4 TABURAN 228Th, 230Th DAN 232Th DI DALAM AIR LAUT DAN SEDIMEN PERMUKAAN DI PERAIRAN PANTAI TIMUR SEMENANJUNG MALAYSIA JALAL SHARIB@SARIP (MINT)

2A-5 210Po/210Pb DALAM AIR HUJAN, AIR SUNGAI DAN AIR LAUT

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SESI KERTAS KERJA LISAN CHE ABD RAHIM MOHAMED (UKM)

2A-6 PENGGUNAAN PENAPIS BIOLOGI TERAKTIF BAGI RAWATAN AIR SISA RAZALI ISMAIL (UTM)

2B Industri I Pengerusi: Prof. Madya Dr. Wan aini Wan Ibrahim (UTM) Bilik: Sri Pontian

2B-1 PENGHASILAN SERTA PENCIRIAN HITAM KARBON DAN KARBON TERAKTIF YANG DIHASILKAN DARIPADA PELBAGAI SISA LIGNOSELULOSA AHMAD MD. NOOR (USM)

2B-2 SYNTHESIS AND CHARACTERISATION OF MOLYBDENUM-VANADIUM BASED OXIDE PREPARED BY THE ANDERSON-TYPE HETEROPOLYMOLYBDATES ROUTE TAN YEE WEAN (UPM)

2B-3 AN ELECTROGENERATIVE PROCESS FOR THE RECOVERY OF GOLD FROM CYANIDE SOLUTIONS YAP CHIN YEAN (USM)

2B-4 KESAN SUHU PUNARAN DALAM MENAMPAKKAN SEMPADAN BUTIRAN ALOI ALUMINIUM AA5083 DENGAN MENGGUNAKAN ASID NITRIK AZMAN JALAR (UKM)

2B-5 INFLUENCE OF PRECIPITATING AGENT ON COPPER(II) OXIDE SYNTHESISED VIA PRECIPITATION METHOD LAU HOOI HONG (UPM)

2B-6 LINKING STUDENTS’ LEARNING PREFERENCES WITH THEIR CONCEPTUAL UNDERSTANDING IN BASIC CHEMISTRY JAAFAR JANTAN (UITM)

2C Elektroanalisis/Penderia I

Pengerusi: Prof. Madya Dr. Md. Sani Ibrahim (USM) Bilik: Sri Muar

2C-1 PHASE BOUNDARY HETEROGENEOUS TIO /ZRO CATALYST FOR EPOXIDATION

2 2

HALIMATON HAMDAN (UTM) 2C-2 TRIIODIDE RESPONSIVE MEMBRANE AND ITS APPLICATION FOR

THE SEQUENTIAL FLOW INJECTION DETERMINATION OF CHLORINE SPECIES WAN TATT WAI (USM)

2C-3 PENGGUNAAN 1-(2-HIDROKSIFENIL)ETHANON BENZOILHIDRAZON (HPEBH) SEBAGAI REAGEN UNTUK PENENTUAN KUANTITATIF AL(III) SECARA SPEKTROFOTOMETRI UL-NAMPAK NURIAH MOHAMAD (UKM)

2C-4 BAHAN PENDERIA pH BERASASKAN REAGEN FENILFLUORON TERPEGUN DALAM MATRIK HIBRID SOL-GEL - KITOSAN ROSMAWANI MOHAMMAD (UKM)

2C-5 VOLTAMMETRIC STUDIES OF CADMIUM ION AT THE MERCURY ELECTRODE IN THE PRESENCE OF GLUTATHIONE M. ZIDAN (UPM)

2C-6 ADSORPTION OF CHROMATE ANION FROM AQUEOUS SOLUTION BY

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SESI KERTAS KERJA LISAN SURFACTANT MODIFIED ZEOLITE Y NIK AHMAD NIZAM (UTM)

2D Organik/Bioteknologi II

Pengerusi: Prof. Madya Dr. Jumat Salimon (UKM) Bilik: Ballroom

2D-1 DPPH FREE RADICAL SCAVENGING, ANTIMICROBIAL AND ANTIAMOEBIC COMPOUNDS FROM ZIZYPHUS MAURITIANA (RHAMNACEAE) HABSAH MOHAMAD (KUSTEM)

2D-2 PRODUCTION OF WATER SOLUBLE AND LOW MOLECULAR WEIGHT CHITOOLIGOSACCHARIDES USING COMMERCIAL MIXED-GLUCANASE FROM ASPERGILLUS ACULEATUSLEE LIH FEN (UKM)

2D-3 SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF A NEW SCHIFF BASE AND ITS COMPLEXES DERIVED FROM 1-(2-THIENYL)-1-PROPANONE M. IBRAHIM M. TAHIR (UPM)

2D-4 PENGHASILAN SURFAKTAN TAK BERION BERASASKAN LAURIL ALKOHOL DARIPADA MINYAK KELAPA SAWITNORHAFIPAH MOHAMAD (UKM)

2D-5 THE OPTIMIZATION OF ACIDIC HYDROLYSIS OF CHITIN BY RESPONSE SURFACE METHODOLOGYCHEE KAH LEONG (UKM)

2D-6 FRACTIONATION OF SUPERCRITICAL FLUID EXTRACT OF ZINGIBER ZERUMBET AND IT’S SKIN WHITENING PROPERTIES MAZITA MOHD. DIAH (SIRIM)

3A Alam Sekitar III

Pengerusi: Prof. Dr. Ibarhim Baba (UKM) Bilik: Sri Mersing

3A-1 KAEDAH MENGURANGKAN COD DALAM AIR KUMBAHAN KILANG PEMBERSIHAN GULA SALIHAN BIN SIAIS (UPM)

3A-2 CHLORPYRIFOS AND MALATHION RESIDUES IN SOILS OF A TERENGGANU GOLF COURSE: A CASE STUDY JURRIFFAH ARIFFIN (KUSTEM)

3A-3 LONG-TERM STUDIES ON THE SALINITY (TDS) AND LEACHING CHARACTERISTICS OF COAL FLY ASH FROM TNB POWER GENERATION PLANTKHOO KOK SIONG (UKM)

3A-4 PRELIMINARY TROPHIC STATE INDEX AND WATER QUALITY ASSESSMENT RESULTS OF TASIK CHINI MAKETAB MOHAMED (UTM)

3A-5 PENENTUAN KEPEKATAN UNSUR-UNSUR SURIH DALAM TANIH SAWAH DI KAWASAN PERLIS SECARA ANALISIS INSTRUMENTASI PENDARFLOUR SINAR-X (XRF)PUI VUI MING (UKM)

3B Industri II

Pengerusi: Prof. Madya Dr. Ahmad Mohd. Nor (USM) Bilik: Sri Pontian

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SESI KERTAS KERJA LISAN 3B-1 PENENTUAN KUALITI AIR TASIK KEJURUTERAAN UKM KAMPUS

BANGI: KE ARAH SISTEM PENGURUSAN SUMBER AIR BERSEPADUMAZLIN MOKHTAR (UKM)

3B-2 KAJIAN PENGEMBANGAN PENGGUNAAN ZEOLIT DARIPADA SEKAM PADI DALAM SISTEM PENAPISAN AIR MINUM NORHASNI RAMLI (UKM)

3B-3 REMOVAL OF BASIC AND REACTIVE DYES: A COMPARISON OF SORPTION AND PHOTODEGRADATION STUDYONG SIEW TENG (UPM)

3B-4 BINARY ION-EXCHANGE OF DIVALENT LEAD AND CADMIUM IN AQUEOUS SOLUTION WITH THE INDIGENOUS IONS OF RICE HUSK ASH-SYNTHESIZED ZEOLITE P TAN SEE HUA (UTM)

3B-5 SYNTHESIS AND PROPERTIES OF ZINC-ALUMINIUM-ANTHRANILATE-NANOCOMPOSITE MAZIDAH MAMAT (UPM)

3C Elektroanalisis/Penderia II

Pengerusi: Prof. Madya Dr. Marcus Jopony (UMS) Bilik: Sri Muar

3C-1 KAJIAN KECEKAPAN ANOD KORBANAN ALOI AL-5.5ZN-2.0MG-XSN DI DALAM AIR LAUT TROPIKAABDUL RAZAK DAUD (UKM)

3C-2 DETERMINATION OF LEAD BY NEW OPTICAL CHROMOGENIC SENSOR ABDUSSALAM SALHIN (USM)

3C-3 Al(III) SENSING USING IMMOBILIZED PAN ENTRAPPED IN SOL GEL FILM BASED ON FLUORESCENCE BEHAVIOR Rita Sundari (UKM)

3C-4 SQUARE WAVE CATHODIC STRIPPING VOLTAMMETRIC TECHNIQUE FOR DETERMINATION OF AFLATOXIN B1 IN GROUND NUT SAMPLEMOHAMAD HADZRI YAACOB (USM)

3C-5 FABRICATION OF CATECHOL BIOSENSOR BASED ON IMMOBILIZED MBTH AND LACCASE ENZYME JAAFAR ABDULLAH (SIRIM)

3D Kimia Tak Organik/Pemangkinan II

Pengerusi: Prof. Madya Dr. Hapipah Mohd. Ali (UM) Bilik: Ballroom

3D-1 SPECTROPHOTOMETRIC DETERMINATION OF ARSENIC (III) BASED ON COMPLEX FORMATION WITH GALLOCYANINE NOR AZAH YUSOF (UPM)

3D-2 X-RAY CRYSTALLOGRAPHY AND BIOLOGICAL PROPERTIES OF ISATIN-2-THIOPHENECARBOXYLIC HYDRAZONE WITH ZINC, NICKEL, CADMIUM, MANGANESE, COBALT AND COPPER COMPLEXES. SITI NADIAH ABDUL HALIM (UM)

3D-3 PHOTOLUMINESCENCE OF EUROPIUM-PICRATE-POLYETHERS COMPLEXES ENY KUSRINI (USM)

3D-4 TINDAK BALAS PENGKOMPLEKSAN ASID-3-(3-BENZOILTIOUREDO) PROPIONIK DENGAN BIS[ASETATOTRIFENILFOSFINARGENTUM(I)] DAN KOBALT(II)KLORIDA

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SESI KERTAS KERJA LISAN NURZIANA NGAH (UKM)

3D-5 PHOTODEGRADATION OF MDEA, PARAQUAT AND PHENOL USING TiO2 AND ZnO BASED PHOTOCATALYSTS: COMPARISON STUDY NORAIDURA AMIN (UTM)

4A Alam Sekitar IV

Pengerusi: Prof. Madya Dr. Mohd. Rozali Othman (UKM) Bilik: Sri Mersing

4A-1 ASSESSMENT OF WATER QUALITY IN SEMENYIH WATER RESOURCE AREA AND HULU LANGAT DOMESTIC WATER SUPPLY ZAINI HAMZAH (UiTM)

4A-2 HEAVY METALS DISTRIBUTION IN URBAN SOIL OF SEBERANG PERAI TENGAH, PULAU PINANG POH SENG CHEE (KUSTEM)

4A-3 ASSESSMENT OF ELEMENTAL POLLUTION IN THE STRAIT OF MELAKAAWAD A. ALZAHRANY (UPM)

4A-4 ANALYSIS OF NATURAL OCCURRING RADIOACTIVE MATERIALS AT AND AROUND KOTA TINGGI WATERFALL IN JOHOR REDZUWAN YAHAYA (UKM)

4B Industri III

Pengerusi: Prof. Madya Dr. Musa Ahmad (UKM) Bilik: Sri Pontian

4B-1 CHARACTERIZATION OF TWO DIFFERENT LIQUID SCINTILLATION COUNTERS: EFFECTS ON AGE DETERMINATION IN RADIOCARBON DATING SYSTEMENORAISHAH OTHMAN (MINT)

4B-2 DECOLOURISATION AND DEGRADATION OF REACTIVE ORANGE 16 DYE IN AQUEOUS SOLUTIONS BY THE CUO/H2O2 PROCESS WONG WAN YUAN (UPM)

4B-3 ANALYSIS OF POLYNUCLEAR AROMATIC HYDROCARBON (PAHs) IN EDIBLE OILS SITI NURDIANA JAAFAR (USM)

4B-4 PREPARATION AND MODIFICATION ACTIVATED CARBON WITH NITRIC ACID (HNO3) LOO LI YIN (UPM)

4C Analisis Am

Pengerusi: Prof. Madya Dr. Norhayati Mohd. Tahir (KUSTEM) Bilik: Sri Muar

4C-1 MICROSCALE CHEMISTRY: AN ALTERNATIVE WAY FOR DOING CHEMISTRY EXPERIMENTS? MASHITA ABDULLAH (USM)

4C-2 CLASSIFICATION OF CHILLI SAUCES : MULTIVARIATE PATTERN RECOGNITION USING SELECTED GCMS RETENTION TIME PEAKS OF CHILLI SAUCE SAMPLESLOW KAH HIN (UM)

4C-3 CORRELATING STUDENTS’ VIEWS ABOUT CHEMISTRY AND THEIR CONCEPTUAL KNOWLEDGE IN FIRST YEAR CHEMISTRYZARILA MOHD SHARIFF (UiTM)

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SESI KERTAS KERJA LISAN 4C-4 KEMAHIRAN PROSES SAINS – SATU WAHANA KE ARAH KEJITUAN

DAN KEPERSISSAN MEMBUAT ANALISIS NAZIYAH KHALID (UPSI)

4D Organik/Bioteknologi III

Pengerusi: Prof. Madya Dr. Sharifuddin M. Zain (UM) Bilik: Ballroom

4D-1 SYNTHESIS AND CHARACTERISATION OF WATER SOLUBLE CHITOSAN DERIVATIVES NOORRASYIDAH MOHD. SARMIN (SIRIM)

4D-2 PRODUCTION OF RESISTANT STARCH FROM HIGH-AMYLOSE STARCH DERIVED FROM ENZYMATIC DEBRANCHING OF SAGO STARCH CHEN SIOW WOON (UKM)

4D-3 SYNTHESIS AND FLUORESCENCE CHARACTERISTIC OF 2-SUBSTITUTED AND 6-SUBSTITUTED PURINESMAIZATUL AKMAN A. BAKAR (UM)

4D-4 TINDAK BALAS PENGETOKSILAN ASID LAURIK BERASASKAN MINYAK KELAPA SAWITZARINA EDRIS (UKM)

5A Alam Sekitar V

Pengerusi: Prof. Madya Dr. Amran Abdul Majid (UKM) Bilik: Sri Mersing

5A-1 WELL WATER QUALITY IN NORTH-EASTERN DISTRICTS OF KELANTAN AHMAD SAAT (UiTM)

5A-2 A PRELIMINARY INVESTIGATION OF INLAND AQUATIC ACIDIFICATION ON SEMENYIH RESERVOIR S.MARIAM SUMARI (UiTM)

5A-3 AKTIVITI Ra DAN Ra Di PERMUKAAN SEDIMEN KAWASAN BAGAN LALANG, SELANGOR

226 228

NIOO SIEW YEW (UKM) 5A-4 REACTIONS OF HEAVY METALS (CU, ZN, FE AND MN) IN ACIDIC

METAL-RICH WATER WITH CALCAREOUS MUDSTONE MARCUS JOPONY (UMS)

5A-5 KERADIOAKTIFAN TABII DAN KANDUNGAN LOGAM BERAT DALAM IKAN DARI SUNGAI ATOK DAN SUNGAI TAHAN , TAMAN NEGARA PAHANGMUHAMAD BIN OTHMAN (UKM)

5B Industri IV

Pengerusi: Dr. Meor Yusoff Meor Sulaiman (MINT) Bilik: Sri Pontian

5B-1 FABRIKASI SENSOR KIMIA OPTIK KAPSAISIN BERASASKAN KAEDAH PENDARFLOUR MUSA AHMAD (UKM)

5B-2 HYDROMETALLURGICAL PROCESS TO SEPARATE LANTHANIDES MD FAZLUL BARI (KUKUM)

5B-3 SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITIES OF SUBSTITUTED SALICYLALDEHYDE-HYDRAZONE AND THEIR METAL COMPLEXES PUVANESWARY SUBRAMANIAM (UM)

viii


SESI KERTAS KERJA LISAN 5B-4 The Effect of pH on the Formation of Zinc/Aluminium-4-Chlorophenoxy Acetate

Nanocomposite SITI HALIMAH SARIJO (UPM)

5B-5 HPW ENTRAPPED IN MESOPOROUS SILICA VIA SOL GEL TECHNIQUE FOR ESTERIFICATION REACTION JUAN JOON CHING (UKM)

5C Tak Org/Pemangkinan III

Pengerusi: Prof. Madya Dr. Abdul Halim Abdullah (UPM) Bilik: Sri Muar

5C-1 KETIDAKTERTIBAN DALAM PENYELESAIAN DAN PENGHALUSAN STRUKTUR MOLEKUL SINAR-X BOHARI M. YAMIN (UKM)

5C-2 POLYMER-ADDED TITANIUM DIOXIDE PHOTOCATALYSTS FOR THE DEGRADATION OF BENZENE AZLIYANA ABDUL RAHMAN (UTM)

5C-3 SYNTHESIS, STRUCTURAL CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF ORGANOTIN(IV) DERIVATIVES WITH CARBOHYDRAZIDE -BIS(SALICYLALDEHYDE) (H CBS): X-RAY CRYSTAL STRUCTURE OF [Me Sn(H CBS)]

4

2 2M. ABU AFFAN (UNIMAS)

5C-4 HYDRAZONE DERIVATIVE CHROMOGENIC REAGENT: SYNTHESIS, CHARACTERIZATION AND ANALYTICAL APPLICATION TEOH BOON SIEW (USM)

5C-5 Bi-Fe PROMOTED VANADIUM PHOSPHATE (VPO) CATALYST FOR THE SELECTIVE OXIDATION OF n-BUTANE TO MALEIC ANHYDRIDE GOH CHEE KEONG (UPM)

6A Alam Sekitar VI

Pengerusi: Prof. Madya Dr. Zaini Hamzah (UiTM) Bilik: Sri Mersing

6A-1 POLYCYLIC AROMATIC HYDROCARBONS IN URBAN SOILS OF KEMAMANNORHAYATI MOHD TAHIR (KUSTEM)

6A-2 PERLAKUAN ISOTOP URANIUM DI PERAIRAN PANTAI TIMUR SEMENANJUNG MALAYSIA: PENENTUAN NISBAH KEAKTIFAN 234U/238U ZAL UYUN WAN MAHMOOD (MINT)

6A-3 ASSESSMENT OF NATURAL RADIOACTIVITY IN WATER AND SEDIMENT FROM AMANG (TIN TAILING) PROCESSING PONDSMOHSEN NASIRIAN (UKM)

6A-4 ASSESSMENT OF HYDROCARBON POLLUTIONS ON COASTAL ENVIRONMENT BY PETROLEUM PROCESSING ACTIVITIES. ABDUL NASIR HAJI SAMOH (USM)

6B Industri V

Pengerusi: Noorrasyidah Mohd Sarmin (SIRIM) Bilik: Sri Pontian

6B-1 COATING THICKNESS MEASUREMENT FOR GOLD BY USING EDXRFMEOR YUSOFF M.S. (MINT)

6B-2 PREPARATION AND CHARACTERIZATION OF CHEMICALLY IMMOBILIZED CROWN ETHER TO MESOPOROUS SILICA FOR SOLID

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SESI KERTAS KERJA LISAN PHASE EXTRACTION (SPE) APPLICATIONS MARDIANA SAAID (USM)

6B-3 SYNTHESIS AND CHARACTERISATION OF MOLYBDENUM OXIDE CATALYSTS FROM CONTROLLED AGEING PROCESS SITI MURNI BINTI M. ZAWAWI (UPM)

6B-4 MOLECULAR RECOGNITION OF A CHROMOGENIC HYDRAZONE DERIVATIVE TOWARDS AMINES ABDASSALAM ABDELHAFIZ (USM)

6C Teknik Pemisahan II

Pengerusi: Prof. Madya Dr. Mohd. Basyaruddin (UPM) Bilik: Sri Muar

6C-1 DETERMINATION OF CAROTENE, TOCOPHEROLS AND TOCOTRIENOLS IN RESIDUE OIL FROM PALM PRESSED-FIBER USING PRESSURIZED LIQUID EXTRACTION-NORMAL PHASE LIQUID CHROMATOGRAPHY M. MARSIN SANAGI (UTM)

6C-2 APPLICATION OF SOLID-PHASE MICROEXTRACTION FOR THE DETERMINATION OF PESTICIDES IN VEGETABLE SAMPLES BY GAS CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTORCHAI MEE KIN (UNITEN)

6C-3 APPLICATION OF SOLID PHASE MICROEXTRACTION (SPME) IN PROFILING HYDROCARBONS IN OIL SPILL CASESZURAIDAH ABDULLAH MUNIR (UiTM)

6C-4 ISOLATION AND PURIFICATION OF LINOLEIC ACID FROM CEIBA PENTANDRA SEED OIL KHAIRUL ASMAK ABD. KADIR (UKM)

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ANALISIS UNSUR DAN KERADIOAKTIFAN DALAM SAMPEL SEDIMEN TASIK CHINI,

PAHANG DARUL MAKMUR

Amran Ab.Majid, Siti Rahimah Umar, Redzuwan Yahaya, Muhamad Samudi Yasir & Mohd Suhaimi Othman

Program Sains Nuklear, Fakulti Sains & Teknologi, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor

Darul Ehsan Email:[email protected]

Abstrak Kajian taburan unsur dan keradioakifan dalam sampel sedimen dari 12 lokasi Tasik Chini telah dilakukan menggunakan teknik spektrometri gama dan analisis pendarfluor sinar-X (XRF). Sebanyak dua belas unsur surih iaitu As, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Zn, Zr, tiga unsur radionuklid tabii iaitu 40K, 238U, 232Th dan satu unsur radionuklid buatan iaitu 137Cs telah dapat dikesan dalam sampel sedimen. Keputusan yang diperolehi menunjukkan nilai kepekatan unsur surih adalah berbeza mengikut lokasi persampelan dan ketiga-tiga radionuklid tabii menunjukkan hampir semua stesen mempunyai kepekatan melebihi had purata dunia dalam tanah. Radionuklid 137Cs telah ditemui di lima stesen tetapi secara kualitatif sahaja. Secara umumnya, kepekatan unsur disetiap stesen berkait rapat dengan aktiviti yang terdapat di stesen masing-masing. Kajian menunjukkan bahawa stesen Laut Jemberau yang terletak berhampiran dengan bekas kawasan perlombongan dan pelbagai gunatanah menunjukkan lokasi yang mengandungi kepekatan unsur As, Co, Cr, Cu, Pb, V dan Zn tertinggi berbanding lokasi lain. Keywords: Sedimen, radionuklid tabii, logam berat. Pengenalan Tasik Chini merupakan tasik semulajadi yang kedua terbesar di Malaysia, di mana ia berada dalam persekitaran asal. Ianya terletak di Mukin Penyur, Pekan, Pahang Darul Makmur pada kedudukan 3o26’–102o55’. Jaraknya dari Kuantan adalah lebih kurang 100 km. Tasik Chini merupakan tasik yang berpola dendritik (berbentuk ranting) dengan keluasan 150 hektar atau 12 km2. Sekitaran Tasik Chini ini dikelilingi oleh hutan tropika. Namun kebanyakan kawasan telah dibalak dan kini ia telah menjadi hutan sekunder dan terdapat juga banyak berlakunya gunatanah di kawasan sekitar Tasik Chini seperti sebagai pusat pelancongan dan pertanian komersil. Malahan terdapat juga bekas kawasan perlombongan di sekitar Tasik Chini. Tasik Chini dijadikan lokasi kajian kerana ia merupakan tasik semulajadi yang menjadi kawasan penempatan penduduk orang asli di mana kawasan tersebut menjadi sumber bekalan air [1&2]. Oleh yang demikian, terdapat satu inisiatif untuk mengkaji kesan aktiviti yang berlaku ini dengan menganalisis unsur dan keradioaktifan di kawasan sekitar Tasik Chini. Ia bertujuan melihat samada pembangunan yang dijalankan ini boleh mengakibatkan pencemaran di kawasan sekitar Tasik Chini atau pun tidak. Jadi dengan menganalisis sedimen dapat memberi gambaran tahap pencemaran air yang boleh mengakibatkan pencemaran logam berat dan dapat mengkaji perkaitan antara kepekatan unsur dengan lokasi persampelan. Sedimen merupakan dasar atau tapak bagi sesebuah tasik di mana ia merupakan perhentian terakhir unsur dan radionuklid serta pemberi “maklumat” terbaik mengenai lokasi kajian. Dalam kajian ini, sedimen Tasik Chini dari pelbagai lokasi telah dianalisis kandungan unsur dan keradioaktifannya menggunakan dua teknik analisis iaitu analisis pendarfluor sinar-X (XRF) dan spektroskopi sinar gama. Eksperimen Lokasi Kajian Sebanyak 15 sampel sedimen telah diambil dari 12 lokasi persampelan di sekitar Tasik Chini pada bulan Mei 2004 seperti yang ditunjukkan dalam Rajah 1.

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Pengumpulan Sampel Sampel sedimen di setiap stesen diambil menggunakan pensampel sediment secara kaut (Ekman). Alat pensampel sediment diturunkan perlahan-lahan menggunakan tali dari bot dengan mulut pengautnya terbuka. Apabila sampai didasar tasik, satu alat penghentak dilurutkan turun melalui tali dan menyebabkan mulut pengaut ini tertutup dan memerangkap sedimen di dasar.

PETA TASIK CHINI

1a

2

3

9a

1b

7

10

9b

12

5

4a

6

4b

811

Ke Segamat

Laut Gumun

Ke Segamat

Laut Pulau Besar

Laut Genting Teratai

Laut Batu Busuk

Laut Melai

Laut Mempiteh

Laut Kenawar

Laut Jemberau

Laut Chenanan

Laut Labun

Laut Serodong

Laut Tanjung Jerangking

Pulau Besar

Pulau Balai

Sg. Gumun

Sg. DatangSg. Chini

RAJAH 1 : Peta lokasi persampelan sediment Tasik Chini Penyediaan dan Rawatan Sampel. Semua sampel dimasukkan ke dalam dulang dan dibersihkan dari bendasing yang nyata dan berat basahnya dicatatkan. Sampel sediment kemudian dikeringkan pada suhu 105oC semalaman dan setelah disejukkan berat keringnya ditentukan. Sampel kemudiaannya dihancurkan dengan menggunakan mortar dan ditapis menggunakan penapis bersaiz 0.5 mm.

Penyediaan Sampel untuk Teknik Pendarfluor Sinar-X Semua sampel sedimen yang telah dihancurkan dan ditapis, perlu ditumbuk halus dan dihomogenkan. Sebanyak 1.00 g sampel sedimen dimasukkan ke dalam radas pembuat pelet

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dengan ditambahkan asid borik sebanyak 6.00 g sebagai pengikat pelet. Setelah itu, sampel bersama asid borik yang dicampurkan tadi diberi tekanan sebanyak 5 tons dan 15 tons untuk mendapatkan palet tertekan yang baik. Pada bahagian belakang palet dilabelkan mengikut stesen masing-masing. Palet seterusnya dimasukkan ke dalam alat pendarfluor sinar-X iaitu Spektrometer PW 1480 (Philips) untuk dianalisis kandungan unsurnya. Bahan piawai yang digunakan adalah basalt. Penyediaan Sampel untuk Teknik Analisis Keradioaktifan. Sebanyak 15 sampel yang diketahui berat masing-masing dimasukkan kedalam botol pembilang kedap udara dan disimpan selama 30 hari bagi mencapai keseimbangan sekular. Analisis keradioaktifan dalam sampel sedimen ditentukan dengan menggunakan sistem spektrometri gama yang terdiri daripada pembilang gama HPGe (Tennelec) dan penganalisis multisalurann berasaskan komputer peribadi untuk analisis keradioaktifan. kandungan keradioaktifan dalam sampel dikrikan secara kaedah bandingan menggunakan Bahan Rujukan Piawai (SRM) yang digunakan ialah Soil-375 (IAEA) sebagai piawai. Masa pembilang sampel dan piawai adalah selama 12 jam.

Hasil Dan Perbincangan Keputusan Analisis Unsur Keputusan analisis kandungan unsur dalam sampel sedimen Tasik Chini menggunakan teknik pendarfluor sinar-X ditunjukkan dalam Jadual 1. Daripada keputusan analisis, sebanyak 12 unsur telah dikesan dalam sampel sedimen Tasik Chini yang terdiri daripada As, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Zn dan Zr. Keputusan kajian menunjukkan bahawa setiap unsur mempunyai kepekatan yang berbeza bagi setiap lokasi persampelan. Secara amnya keputusan mendapati Laut Jemberau mempunyai kepekatan yang paling tinggi bagi unsur As, Co, Cr, Cu, Pb, V dan Zn dengan kepekatan masing-masing unsure sebesar 50, 46, 113, 68, 156, 156 dan 1679 ppm. Dua bekas lombong besi dan barit serta kedudukanyan yang berdekatan dengan Laut Gumun dan terdapatnya kawasan pelancongan Tasik Chini, pembukaan FELDA, penempatan dan yang terbaru ialah Pusat Latihan Khidmat Negara dipercayai menyumbang terhadap kandungan unsur yang tinggi ini. Hal ini menunjukkan sememangnya perlombongan dan pembangunan yang terdapat di sekitar lokasi persampelan mempengaruhi kepekatan unsur dan keputusan ini mempamerkan sedimen boleh bertindak sebagai sinki kepada pencemaran akuatik sebagaimana yang dilaporkan oleh Mouhi et.al (2003) [3]. Kajian para penyelidik Kanada di Tasik Killarney, Canada mendapati sampel dari kawasan perindustrian mempunyai unsur-unsur kadmium, kuprum, plumbum, nikel dan zink manakala pada kawasan yang masih lagi terpelihara terdapat unsur-unsur ferum, mangan, arsenik dan kobalt [4]. Kajian lain pula melaporkan arsenik biasanya ditemua dalam sedimen tasik dengan kepekatan 1 - 15 ppm [5]. Menurut Fytianos dan Laurantou (2004) [6] dalam kajiannya terhadap sampel sedimen di Tasik Volvi dan Koronia di Greece terdapat tujuh unsur yang dapat dikesan iaitu kadmium, plumbum, kromium, kuprum, mangan, zink dan ferum. Sampel ini diambil di dua keadaan cuaca yang berbeza dan kedua-dua tasik ini merupakan tasik yang masih belum tercemar.

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Krumgalz dan Fainshtein (1991) [7] pula melaporkan sedimen bagi kawasan Haifa Bay yang berdekatan dengan kawasan perindustrian dan perbandaran menunjukkan terdapat pengumpulan merkuri, plumbum, zink, kadmium, ferum dan kuprum. Kuprum, zink, plumbum dan kadmium juga ditemui dalam sedimen Kenyan Coast. Kajian oleh Mouhi et.al (2003) [3] juga mendapati kawasan persampelan sediment Makupa yang berdekatan dengan kawasan perindustrian dan pelupusan sampah tinggi kandungan unsur. Sebagai contoh mereka mendapati kepekatan masing-masing kupram, zink, plumbum dan kadmium adalah setinggi 102.0 ± 46.0, 1017.0 ± 840.0, 103.0 ± 35.8, dan 51.0 ± 14.3 manakala kepekatan unsur kawasan Port Reitz Creek yang kurang tercemar adalah kuprum, 21.6 ± 7.1; zink, 57.1 ± 17.9; plumbum, 26.2 ± 11.6 dan kadmium, 1.38 ± 14.3. Menurut Kamaruzzaman et. al (2004) [8], kepekatan logam berat dalam sedimen dipengaruhi oleh pelbagai faktor seperti ciri sedimen, jenis, kualiti bahan organik dan saiz partikel sedimen itu sendiri. Kajian oleh Suhaimi-Othman & Tan (2004) [9], pula saiz butiran sedimen memainkan peranan penting dalam menentukan keupayaan menjerap logam di mana pengurangan saiz sedimen didapati meningkatkan keupayaan memerangkap logam. Analisis keradioaktifan tabii Selain kandungan unsur, analisis keradioaktifan juga telah ditentukan menggunakan spektrometri gama seperti yang diberikan dalam Jadual 2. Keputusan analisis menunjukkan kepekatan radionuklid tabii bagi masing-masing uranium-238, torium-232 dan kalium-40 pada hampir semua stesen mencatatkan bacaan melebihi had purata dunia. Kajian menunjukkan purata kepekatan uranium-238 adalah 191.0 ± 94.7 Bq/kg (14.5 ± 7.2 ppm) manakala bagi torium-232 pula ialah 160.3 ± 32.8 Bq/kg (39.5 ± 8.9 ppm) iaitu 5 atau 6 kali lebih tinggi berbanding kepekatan purata dunia. Walau pun kepekatan Th-232 dan U-238 lebih tinggi, tetapi nisbah Th:U masih lagi 3:1. Ini menunjukkan pertambahan U-238 dan Th-232 berpunca dari sumber tabii. Bagi kawasan kajian Tasek Chini ini, aktiviti perlombongan serta jenis batuan yang terdapat disini dijangka banyak mempengaruhi nilai keradioaktifan tabii yang tinggi ini. Peningkatan kepekatan uranium-238, torium-232 dan kalium-40 di kerak bumi secara umumnya semakin tinggi apabila kandungan SiO2 dan K2O dalam kerak bumi semakin tinggi [10,11].

Keputusan kajian ini juga menemukan radionuklid buatan manusia iaitu Cs-137 di lima stesen secara kualitatif iaitu Laut Gumun (1a,1b), Laut Mempiteh (6), Laut Melai (9b) dan Laut Labun (11). Radionuklid buatan Cs-137 memang boleh ditemui dalam sampel yang tidak terganggu kerana ianya berpunca dari radionuklid guguran. Kajian oleh Muhamad Omar [12] melaporkan kehadiran Cs-137 antara 0.2 – 10.0 Bg/kg bagi beberapa sampel tanah di Malaysia. Kesimpulan Kajian penentuan unsur dalam sampel sedimen Tasik Chini menggunakan teknik pendarfluor sinar-X telah dapat mengesan 12 unsur. Unsur-unsur tersebut ialah As, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Zn dan Zr. Kesemua unsur ini mempunyai kepekatan yang berbeza di setiap lokasi kajian iaitu As (11-50 ppm), Ba (553-944 ppm), Co (8-46 ppm), Cr (82-113 ppm), Cu (11-68 ppm), Ni (67-193 ppm), Pb (37-156 ppm), Rb (105-149 ppm), Sr (18-127 ppm), V (93-156 ppm), Zn (147-1679 ppm) dan Zr (190-290 ppm). Walaupun persekitaran Tasik Chini dikatakan masih lagi terpelihara, namun terdapat juga kepekatan unsur yang tinggi terutamanya di Laut Jemberau. Sebanyak tujuh jenis unsur di laut ini mempunyai kepekatan

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paling tinggi jika dibandingkan dengan lokasi kajian yang lain. Unsur tersebut ialah As (50 ppm), Co (46 ppm), Cr (113 ppm), Cu (68 ppm), Pb (156 ppm), V (156 ppm) dan Zn (1679 ppm). Kawasan Laut Jemberau ini dikelilingi oleh banyak aktiviti manusia seperti berdekatan dengan kawasan carigali barit, pembalakan dan pembukaan tanah untuk pembinaan FELDA dan kawasan rekreasi serta berdekatan dengan kawasan pelancongan Tasik Chini di Laut Gumun dan lombong besi di bahagian selatan Laut Jemberau. Kajian juga menemukan kepekatan radionuklid tabii uranium-238, torium-232 dan kalium-40 dalam sediment Tasik Chini melebihi nilai purata kepekatan dunia tetapi bersumberkan secara tabii. Selain itu radionuklid guguran Cs-137 turut ditemui di lima lokasi kajian secara kualitatif sahaja. Rujukan:

1. ERINCO. 1992. Kuala Sungai Chini Gateway Development Plan Vol 1. Petaling Jaya: ERINCO. 2. ERINCO. 1993. Tasik Chini Eco Tourism Development Study Environment Impact Assesment Vol II.

Petaling Jaya: ERINCO. 3. Muohi, A.W., Mavuti, K.M., Omondi, J.G. & Onyari, J.M. 2003. Heavy metals in sediments from

Makupa and Port-Reitz Creek systems: Kenyan Coast. Environment International. 28: 639-647. 4. Nelson , B., Chen, Y. W., Gunn, J. M. & Dixit, S. S. 2004. Sediment Trace Metal Profiles in Lakes of

Killarney Park, Canada from Regional to Continental Influence. (atas talian) http://www.sciencedirect.com/science?_ob=ArticleURL&_udi (14 September 2004)

5. Lollar, B. S. 2004. Treatise on Geochemistry Environmental Geochemistry. Ed. ke-9.Oxford: Elsevier Pergamon.

6. Fytianos, K. & Lourantou, A. 2004. Speciation of elements in sediment samples collected at lakes Volvi and Koronia, N.Greece. Environment International. 30(1):11-17.

7. Krumgalz, B. S. & Fainshtein, G. 1991. Trace Metal and Organic Matter in Nearshore Sediment Cores from the Eastern Mediterranean (Haifa Bay of Israel). Marine Environmental Research. 31: 1-15.

8. Kamaruzzaman, B. Y., Ong, M. C. & Willison, K. Y. S. 2004. Taburan Kepekatan Elemen-elemen Kimia di dalam Teras Sedimen di Hutan Paya Bakau Paka, Terengganu. Prosiding Simposium Kimia Analisis Malaysia Ke-17.

9. Suhaimi-Othman, M. & Tan, B. F. 2004. Kajian Kandungan Logam Berat (Cu, Cd, Zn dan Pb) di dalam Air, Sedimen dan Udang Air Tawar Macrobrachium Ianchesteri di Sungai Langat. Prosiding Simposium Kimia Analisis Malaysia Ke-17.

10. International Atomic Energy Agency (IAEA). 1990. The Use of Gamma Ray Data To Define The Natural Radiation In Environment. IAEA-TECDOC_566, Vienna: IAEA.

11. Khursyid Alam Butt, Amanat Ali & Aziz Ahmad Qureshi. 1998. Estimation of Environmental Gama Background Radiation Levels in Pakistan. Health Physics. 75(1): 63-66.

12. Muhamat Omar (1991), Environmental Radiation and Its Relation with Man. Nuclear Buletin of Malaysia. 1(2). 16-18.

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http://www.sciencedirect.com/science?_ob=ArticleURL&_udi


Jadual 1 : Keputusan analisis unsur bagi setiap stesen persampelan

Kepekatan (ppm)

Stesen

As

Ba

Co

Cr

Cu

Ni

Pb

Rb

Sr

V

Zn

Zr

1a: Laut Gumun 21 571 20 92 43 125 67 119 75 134 326 226 1b : Laut Gumun 14 888 26 87 57 128 50 136 18 134 1145 290 2: Laut P. Balai 15 557 Lod 90 60 157 76 132 101 130 147 208 3: Laut Chenanan 13 553 Lod 99 66 78 65 105 59 142 260 190 4a: L. Tanjung Jerangking

12 714 22 95 11 143 48 128 99 139 693 225

4b: L. Tanjung Jerangkin

17 603 26 87 44 149 39 133 100 130 329 235

5: Laut Genting Teratai

15 630 Lod 96 60 101 38 119 78 127 321 201

6: Laut Mempiteh 13 714 15 96 60 141 44 131 93 147 645 227 7: Laut Senawar 11 824 26 96 20 189 37 138 113 126 655 249 8: Laut Serodong 13 944 24 98 49 145 46 129 98 148 948 274 9a: Laut Melai 17 582 Lod 85 68 186 56 149 127 117 488 230 9b: Laut Melai 15 831 35 82 Lod 151 61 120 88 117 1130 284 10: Laut Batu Busuk

13 651 25 83 55 146 83 131 92 105 1097 211

11: Laut Labun 18 555 8 87 54 193 59 146 104 93 1032 209 12: Laut Jemberau 50 782 46 113 68 67 156 109 23 156 1679 221 Min 17.1

± 9.5

693.3 ±

132.1

18.2 ±

14.1

92.4 ±

8.0

47.7 ±

21.1

140.0 ±

36.8

61.7 ±

29.5

128.3 ±

12.3

84.5 ±

30.5

129.7 ±

16.7

726.3 ±

433.5

232.0 ±

30.0 Had pengesan (Lod)

0.5 2 1 2 1 1 1 0.5 0.5 1 1 0.5

Lod – di bawah had pengesanan

Jadual 2: Kepekatan radionuklid tabii sampelsediemn Tasik Chini Stesen Kepekatan radionuklid Nisbah

K-40 (Bq/kg)

Th-232 (Bq/kg)

Th-232 (ppm)

U-238 (Bq/kg)

U-238 (ppm)

Th:U

Laut Gumun: 1a 599 126.8 32.0 215.6 16.0 2 : 1 Laut Gumun: 1b 757 109.8 28.0 130.7 10.0 3 : 1 L. Pulai Balai: 2 549 189.7 48.0 225.8 17.0 3 : 1 Laut Chenanam: 3 674 206.7 52.0 268.4 20.0 3 : 1 L. Tanj. Jerangking: 4a 713 139.3 35.0 142.1 11.0 3 : 1 L. Tanj. Jerangking:4b 594 143.7 36.0 114.0 9.0 4 : 1 L. Genting Teratai: 5 690 178.8 45.0 170.2 13.0 4 : 1 Laut Mempiteh: 6 656 152.2 39.0 135.9 10.0 4 : 1 LautKenawar: 7 760 152.1 39.0 90.5 7.0 6 : 1 Laut Serodong: 8 818 105.9 27.0 151.3 12.0 2 : 1 Laut Melai: 9a 537 160.3 41.0 54.5 4.0 10 : 1 Laut Melai: 9b 741 170.5 27.0 153.5 12.0 2 : 1 L. Batu Busuk: 10 435 168.3 43.0 400.5 31.0 1 : 1 Laut Labun: 11 475 221.4 56.0 292.8 22.0 3 : 1 Laut Jemberau: 12 277 178.8 45.0 319.3 24.0 2 : 1 Min 618.3

± 1454 160.3

± 32.8 39.5

± 8.9 191.0

± 94.7 14.5

± 7.2 3:1

UNSCEAR (tanah) [14]. 400 - 6.3 - 2.0 3:1

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PYROLYSIS AND LIQUEFACTION OF ACETONE AND MIXED ACETONE/TETRALIN SWELLED MUKAH BALINGIAN MALAYSIAN SUB-

BITUMINOUS COAL – THE EFFECT ON COAL CONVERSION AND OIL YIELD

Mohd Fauzi Abdullah*, Mohd Azlan Mohd Ishak and Khudzir Ismail

Fuel Combustion Research Laboratory

Faculty of Applied Sciences University Technology MARA

Arau Campus, 02600, Arau, Perlis *e-mail: [email protected]

Abstract. The effect of swelling on Mukah Balingian (MB) Malaysian sub-bituminous coal macrostructure was observed by pyrolysing the swelled coal via thermogravimetry under nitrogen at ambient pressure. The DTG curves of the pyrolysed swelled coal samples show the presence of evolution peaks at temperature ranging from 235 – 295 °C that are due to releasing of light molecular weight hydrocarbons. These peaks, however, were not presence in the untreated coal, indicating some changes in the coal macrostructure has occurred in the swelled coal samples. The global pyrolysis kinetics for coal that follows the first-order decomposition reaction was used to evaluate the activation energy of the pyrolysed untreated and swelled coal samples. The results thus far have shown that the activation energy for the acetone and mixed acetone/tetralin-swelled coal samples exhibit lower values than untreated coal, indicating less energy is required during the pyrolysis process due to the weakening of the coal-coal macromolecular interaction network Moreover, liquefaction on the these swelled coal samples that was carried out at temperatures ranging from 360 to 450 °C at 4 MPa of nitrogen pressure showed the enhancement of the coal conversion and oil yield at temperature of 420 °C, with retrogressive reaction started to dominate at higher temperature as indicated by decreased and increased in oil yield and high molecular weight pre-asphaltene, respectively. These observations suggest that the solvent swelling pre-treatment using acetone and mixed acetone/tetralin can improve the coal conversion and oil yields at less severe liquefaction condition. Keywords: Swelling, liquefaction, pyrolysis, coal conversion, oil yield. Introduction

Coal liquefaction is usually carried out at temperatures higher than 400 °C and at relatively high pressure. Many attempts have been made to develop methods of dissolving coal at less severe conditions in order to increase coal liquefaction efficiency [1-4] and to reduce capital and operation costs [5]. It is known that, by lowering reaction severity, coal conversion reaction rates and liquid product yields will also be reduced, unless the intrinsic coal reactivity can be sufficiently enhanced [4]. Joseph [1] reported that pre-swelled US bituminous and lower rank coals (i.e. sub-bituminous and lignite) with tetrabutylammonium hydroxide, tetrahydrofuran and methanol prior to liquefaction at 400 °C and at 7.6 MPa enhanced coal conversion and product quality. He found that the enhancement depends on the coal rank and the type of swelling agent being used and suggested that the beneficial effect of swelling might be due to the expansion of the coal macromolecular structure, making it more accessible to the hydrogen donor solvent during liquefaction. In another work, Simsek et al.

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[2] studied the effect of pre-swelling with various organic solvents and acid-demineralised (pre-treatment) Turkish coals on the supercritical toluene extract yield at 350 °C and at 7 MPa. They found that the highest improved liquid yields for each coal was obtained by the combined effects of pre-treatment and pre-swelling of coals. Although the combination effects proved to increase liquid yields, no simple trend between reactivity improvements with properties of the coals was observed.

In our recent study [6], we carried out the solvent swelling pre-treatment using hydrogen and non-hydrogen-bonding solvents on low-rank Malaysian coal. The pyrolysis of the untreated and swelled coal using thermogravimetric analyzer (TGA) under nitrogen atmosphere thus far has shown that the activation energy barrier in the swelled coals was lower with an increase in the volatile yield in comparison to the untreated sample. Moreover, the results of the treated samples also show the increase of coal reactivity as revealed by DTG results. Thus, these preliminary results might provide useful information for coal extraction and liquefaction processes. Hence, this study investigates the effect of acetone and mixed acetone/tetralin-swelled, respectively on the pyrolysis behaviours using TGA and the conversion and product yields from the liquefaction using 1-liter high-pressure high-temperature batch-wise reactor system with tetralin as the hydrogen-donor solvent. Materials And Methods

Coal Preparation The sample used in this study is Mukah Balingian (MB) originating from Sarawak, Malaysia. The procedure for coal preparation has been reported earlier [7]. Table 1 represents the ultimate, proximate and petrography analyses of the untreated MB coal sample. Solvent Swelling Procedure The volumetric method described by Onal et al. [8] was adopted in the measurement of swelling ratio without density correction. Acetone (analytical grade solvent from Fisher Chemicals) is used as swelling solvent. For the mixed solvent, which consists of acetone and tetralin, the volume mixed ratio was 80:20. The swelling ratio of the coal samples was measured at room temperature (30 °C) and at ambient pressure. After the swelling procedure, the swelled coal was filtered, dried in vacuum-oven at 80 °C for overnight and finally stored in bottle prior to liquefaction experiments. The determination of activation energy and volatile yield of the coal samples have been reported earlier [6]. The results of swelling ratio, activation energy and pyrolysis volatile yields of the coal samples are given in Table 2. Coal Liquefaction Experiments All liquefaction experiments were carried out in a 1-liter magnetically stirred (at 500 rpm) high-pressure high-temperature batch-wise reactor (Parr, 4571 model) fitted with stainless steel tubing condenser cooled with ice to ensure maximum capture of the volatile materials. The procedure of coal liquefaction has been reported earlier [7]. Briefly, 20 g of untreated or acetone-swelled coal and 200 g of tetralin were mixed in the reactor and the liquefaction was carried out at temperature ranging from 360 – 450 °C and at 4 MPa nitrogen pressure. However, for mixed acetone/tetralin coal sample, the reaction temperature used was at 420 °C. After reaching at the particular temperature, the reaction was held for 30 minutes before

8


the system was cooled to ambient temperature. Coal conversion and the product yields of all the samples were finally evaluated [7] and are shown in Table 3. Sample Analyses The procedure of ultimate and proximate analyses has been reported earlier [7]. The ultimate analyses were carried out using Elemental Analyser Leco 932 model. The proximate analyses were done using Thermogravimetric analyzer DTA/DSC TA model SDTQ600 under nitrogen gas atmosphere with heating condition follows the ASTM D2974 [9]. Table 1: Characteristics of MB coal sample. Table 2: Results of swelling ratio (Q), activation energy (Ei, kJ/mol) and Ultimate Proximate pyrolysis volatile yield (VY) of MB coal. analysis (wt% daf) analysis (wt% db) Sample Q Ei VY (%) Carbon 63.9 Volatile matter 44.7 Hydrogen 5.1 Fixed carbon 51.1 Untreated 1.0 312.2 37.6 Nitrogen 1.9 Ash content 4.2 Tet-sw 1.0 246.3 41.4 Sulphur 0.5 Ace-sw 1.3 230.5 40.4 Oxygen* 28.6 Ace+Tet-sw 1.4 131.6 49.8 Calorific value = 24.60 MJ/kg Tet-sw = Tetralin-swelled; Ace-sw = Acetone-swelled; *Calculated by difference. Ace+Tet-sw = Acetone/Tetralin-swelled. Results And Discussion Effect of Swelling On Coal by Pure and Mixed Solvents During Pyrolysis Table 2 shows the results of swelling ratio, activation energy and volatile yield of untreated, acetone-swelled and mixed acetone/tetralin-swelled of MB coal samples. From the table, it can be seen that the swelling ratios of the coal in acetone and mixed acetone/tetralin are higher than that of tetralin. This observation indicates the interaction of nucleophile in the H-bonding solvent (i.e. acetone) with the reactive sites such as hydroxyl, carboxyl and carbonyl that are presence in the coal forming hydrogen bondings. The increase in solvent-coal interactions enhanced the bonds strength, thus weakened the coal-coal macromolecular interactions, and promotes the swelling process of the coal. Tetralin, which is a non-H-bonding solvent, however, did not exhibit any swelling activity with the swelling ratio value closed to that of untreated coal [6]. Interestingly, when tetralin was mixed with acetone, the swelling ratio of the coal increased to a value of 1.4, which is slightly higher than the pure acetone. This minor increment indicates an additional interaction occurred between the coal macromolecular network and the solvents mixture. The effect of swelling by the mixed solvents seem to weakens the coal macromolecular network rigidity and promotes the

9


diffusion of the solvent mixtures, though the exact mechanism is still not well understood. Further, in order to prove this effect, the solvent pre-swelled and untreated coal samples were subjected to pyrolysis via thermogravimetric analysis and the activation energy of the process was evaluated. The global pyrolysis kinetics for coal that follows the first-order decomposition reaction was used to determine the activation energy of the process [10]. Indeed, the mixed solvent swelled coal exhibits the lowest activation energy with an increased in volatile yield, indicating less energy was required during the pyrolysis process due to the weakening of the coal-coal macromolecular interaction network that occurred during swelling process. Thus, this observation indicates the presence of synergistic effect of the mixed solvent towards swelling activity of the coal that enhanced the lowering of the activation energy with an increased in volatile yield during pyrolysis.

Figure 1 shows the DTG curves of untreated, acetone-swelled and mixed acetone/tetralin-swelled coal during pyrolysis. Apparently, both the pyrolysed acetone and mixed acetone/tetralin-swelled coal samples show the presence of evolution peaks at temperatures ranging from 175 to 395 °C that are due to the releasing of the light molecular weight hydrocarbons [10]. These peaks however, were absence in the untreated coal. Another point of interest is that for the mixed acetone/tetralin-swelled coal sample there appears to be another evolution peaks at high temperature ranging from 500 to 650 °C that are due to the released of heavy hydrocarbons [10], and were not presence apparently in both untreated and acetone pre-swelled coal samples. Hence, these observations further proves that some changes in the coal macrostructure have occurred especially in the mixed solvents swelled coal sample that promotes the released of light and heavy molecular weight hydrocarbons during pyrolysis. Hence, this shows that the swelling pre-treatment on coal would possibly increase the liquefaction performance by increasing coal conversion and product yields (especially percent oil) at less severe conditions.

Figure 1: The DTG curves of untreated, acetone-swelled and mixed acetone/tetralin-swelled of MB coal samples.

10


Effect of Swelling on Coal Conversion and Oil Yield Table 3 shows the percent of coal conversion and product yields of liquefaction on the untreated, acetone-swelled and mixed acetone/tetralin-swelled coal samples. Table 3: Liquefaction results of untreated, acetone- and mixed acetone/tetralin-swelled coal. Product yields Temp. (°C) % Coal conversion % Oil+gas % Asphaltene % Preasphaltene Unt. Ace. Mix. Unt. Ace. Mix. Unt. Ace. Mix. Unt. Ace Mix 360 42 35 - 28 24 - 8 5 - 6 6 - 380 57 43 - 44 29 - 8 3 - 5 11 - 400 66 62 - 50 46 - 10 6 - 6 10 - 420 84 86 86 67 70 78 10 6 1 7 10 7 450 90 83 - 80 75 - 8 4 - 2 4 - Unt. = Untreated; Ace. = Acetone-swelled; Mix. = Mixed acetone/tetralin-swelled. Liquefaction conditions: 4 MPa, 1:10 coal:solvent, 30 min reaction time and stirred at 500rpm. Apparently, the results thus far showed that the percent of coal conversion and oil yield obtained during liquefaction of acetone-swelled coal was lower than the untreated coal with preasphaltene predominantly increased at temperature below 400 °C. The fact that as the liquefaction temperature increased at above 350 °C, the coal starts to soften and eventually undergo fragmentation forming preasphaltene and asphaltene [7]. However, with the swelled coal sample, much smaller molecules are being formed due to the weakening of the coal-coal macromolecular interaction as revealed by the DTG curves. The hydrogen donor solvent should cap these smaller radical molecules rapidly in order to prevent repolymerisation reaction. The fact that high formation of preasphaltene suggests that repolymerisation reaction starts to dominate due to the inability of the donor solvent to cap these smaller molecules at temperature below 400 °C. However, as the liquefaction temperature increased beyond 400 °C, a high amount of coal conversion and oil yield being obtained with decreased amount of preasphaltene formation. Obviously, the effect of mixed solvent swelled coal during liquefaction can be seen by the high percent of oil yield of 78 % at 420 °C, that is higher than that achieved in the acetone- swelled and untreated coal samples. The increase in oil yield corresponds to the decrease in asphaltene and preasphaltene. These observations seem to agree with the pyrolysis which resulting in the lowest activation energy with the greater increased of volatile yield that indicate the high reactivity of the mixed acetone/tetralin-swelled coal. Thus, these phenomenons proved the beneficial effect of mixed solvent-swelled coal in enhancing coal conversion and oil yield prior to liquefaction.

11


Conclusion The effect of acetone and mixed acetone/tetralin-swelled on the coal pyrolysis using TGA and the liquefaction products using 1-liter high-pressure high-temperature batch-wise reactor system with tetralin as the hydrogen-donor solvent were studied. The results thus far have shown that the activation energy for the acetone and mixed acetone/tetralin-swelled coal samples exhibit lower values than the untreated coal, indicating less energy is required during the pyrolysis process due to the weakening of the coal-coal macromolecular interaction network. Moreover, liquefaction on the swelled coal samples showed the enhancement of the coal conversion and oil yield at temperature of 420 °C, where the oil yield was greatly increased for mixed acetone/tetralin-swelled with further decreased in asphaltene and preasphaltene, respectively. Thus, these observations proved the beneficial effect of swelling pre-treatment on liquefaction at less severe condition. Acknowledgements The authors would like to thank the Ministry of Science Technology & Innovation, Malaysia for funding the research (grant no.: 02-02-01-0017-EA0017) and University Technology MARA for supporting the research work. References 1. Joseph, J.T., “Liquefaction behaviour of solvent-swollen coals”, Fuel, vol. 70, pp. 139-

144, 1991. 2. Simsek, E.H., “The effect of pre-swelling and/or pre-treatment of some Turkish coals

on the supercritical fluid extract yield”, Fuel, vol. 81, pp. 503-506, 2002. 3. Hu, H., Sha, G. and Chen, G., “Effect of solvent swelling on liquefaction of Xinglong

coal at less severe conditions”, Fuel, vol. 68, pp. 33-43, 2000. 4. Artok, L., Davis, A., Mitchell, G.D. and Schobert, H.H., “Swelling pre-treatment of

coals for improved catalytic liquefaction”, Fuel, vol. 71, pp. 981-991, 1992. 5. Shams, K.G., Miller, R.L. and Baldwin, R.M., “Enhancing low severity coal

liquefaction reactivity using mild chemical pre-treatment”, Fuel, vol. 71, pp. 1015-1023, 1992.

6. Abdullah, M.F., Ismail, K. and Ishak, M.A.M., “Investigation of pyrolysis behaviours on solvent swelled Mukah Balingian coal using TGA analysis”, ACGC Chemical Research Commun., in print.

7. Ishak, M.A.M., Ismail, K., Abdullah, M.F., Kadir, M.O.A., Mohamed, A.R. and Abdullah, W.H., “Liquefaction studies of low-rank Malaysian coal using high-pressure high-temperature batch-wise reactor system”, Coal Preparation Jour., in print.

8. Onal, Y. and Akol, S., “Influence of pre-treatment on solvent-swelling and extraction of some Turkish lignites”, Fuel, vol. 82, pp. 1297-1304, 2003.

9. ASTM D2974, Annual Book of ASTM Standards, vol. 5.05, The American Society for Testing and Materials (ASTM), Philadelphia, PA.

10. Probstein, R.F. and Hicks, R.E., ‘Synthetic fuels’, McGraw-Hill, Inc., 1982.

12


KANDUNGAN LOGAM BERAT DAN RADIONUKLID TABII DALAM IKAN, AIR, TUMBUHAN DAN SEDIMEN DI BEKAS TASIK LOMBONG

Muhamad Samudi Yasir, Norlaili bt Ahmad Kabir, Redzuwan Yahaya & Amran Ab Majid

Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor. [email protected]

Abstrak: Tasik bekas lombong bijih timah di Malaysia kini giat ditebusguna untuk kegiatan pertanian, akuakultur, kawasan rekreasi atau dijadikan sebagai kawasan perumahan dan perindustrian. Kesan aktiviti perlombongan boleh menyebabkan peningkatan kepekatan atau pengkayaan radionuklid tabii dan logam berat terhadap ekosistem. Maka, kajian telah dilakukan untuk menentukan kandungan radionuklid tabii dan 12 unsur logam berat (Hf, Zr, Mn, Cu, Zn, As, Cd, Sn, Sb, Ba, Hg dan Pb) di dalam ikan, air, tumbuhan dan sedimen di tiga tasik bekas lombong sekitar Puchong dan Sepang, Selangor Darul Ehsan. Analisis dilakukan menggunakan ICP-MS. Secara keseluruhannya kepekatan logam berat adalah tinggi dalam sedimen serta tumbuhan berbanding dengan dalam ikan dan air. Barium mencatatkan kepekatan yang tinggi dikesan di dalam sedimen dan air, manakala zink dan mangan paling tinggi dikesan masing-masing dalam ikan dan tumbuhan. Kesemua unsur logam berat dalam ikan berada di bawah paras maksimum cemaran logam yang dibenarkan oleh Akta Makanan (Akta 281) dan Peraturan-Peraturan 1983 kecuali bagi kepekatan merkuri bagi ikan di lombong kedua iaitu 0.53 ± 0.20 mg/kg) yang melebihi had yang dibenarkan iaitu 0.5 mg/kg. Aktiviti radionuklid thorium (Th-232) dan uranium (U-238) dalam sedimen adalah tinggi berbanding dalam ikan, air dan tumbuhan dengan masing-masing berada dalam julat (30.76 ± 2.71 – 35.34 ± 0.27 Bq/kg) dan (9.37 ± 2.30 - 26.32 ± 3.01 Bq/kg). Manakala aktiviti kalium (K-40) dalam tumbuhan dan ikan didapati lebih tinggi berbanding di dalam air dan sedimen. Katakunci: Logam berat, radionuklid tabii, tasik bekas lombong, ikan, sedimen Abstract: Malaysia aggressively reclaimed most of their disused tin-mining pool especially for agricultural activities, freshwater fish farming area, recreational area, houses area and even as an industrial area. Past mining activities might induced the concentration of naturally occurring radionuclide (NORM) and heavy metal at the disused tin-mining pool ecosystem. A study has been conducted on the status of heavy metal (Hf, Zr, Mn, Cu, Zn, As, Cd, Sn, Sb, Ba, Hg and Pb) concentration and naturally occurring radionuclide activity in fish, water, plants and sediments at three different disused tin-mining pool near by Sepang and Puchong, Selangor Darul Ehsan. Sample of fish, water, plant and sediment being analyze using ICP-MS. The concentrations of heavy metal in sediment and plant are higher than its concentrations in fish and followed by water. The highest concentration of heavy metal in sediment and water is barium, whereas the highest concentration of heavy metal in fish and plant is zinc and manganese. The result also showed that only mercury level in fish collected in second disused tin-mining pool (0.53 ± 0.20 mg/kg) is exceed the maximum limit (0.5 mg/kg) prescribe by the Malaysian Food Act (Act 281). The activity of U-238 and Th-232 in sediment was found to be relatively higher than its activity in fish, plant or water (30.76 ± 2.71 – 35.34 ± 0.27 Bq/kg) and (9.37 ± 2.30 -18.86 ± 2.60 Bq/kg). The determination of K-40 activity showed that it is highly contained in plant and fish than in sediment or water. Keywords: Heavy metal, natural radiobuclides, ex-mining lake, fish, sedimen Pendahuluan. Malaysia satu ketika dahulu merupakan salah sebuah negara pengeluar utama timah dunia. Malah pembangunan Lembah Kelang dan Lembah Kinta mempunyai kaitan yang rapat dengan penemuan timah. Walaupun kini tidak banyak lagi lombong timah yang masih aktif beroperasi, ujud pula industri sampingan seperti pengekstrakan pelbagai mineral berharga dari amang (zirkon, ilmenit dan struverit). Salah satu peninggalan industri perlombongan timah ialah bekas tasik lombong yang dikategorikan sebagai tasik buatan. Kini tasik dan kawasan bekas lombong ini telah banyak ditebus guna untuk dimajukan sebagai kawasan perumahan dan perindustrian, ditanami rumput untuk tujuan penternakan, akuakultur atau pun dijadikan kawasan rekreasi (Amran Ab Majid et al. [1]). Selain bijih timah, perlombongan turut sama mengeluarkan pelbagai jenis mineral lain dari perut bumi. Sekiranya mineral sampingan ini terdiri daripada logam berat, dikhuatiri sisanya masih tertinggal di kawasan bekas lombong yang kini telah dijadikan kawasan pertanian, perternakan ataupun akuakultur. Bagi tujuan akuakultur, proses bioakumulasi logam berat boleh terjadi yang akhirnya berkemungkinkan memasuki rantai makanan ekosistem bekas lombong tersebut. Oleh itu, ikan yang merupakan sebahagian daripada komponen rantai makanan dalam ekosistem tasik ini mungkin akan turut tercemar dengan sisa logam berat tersebut. Keadaan yang sama mungkin juga berlaku kepada radionuklid tabii seperti U-238, Th-232 dan K-40. Kemasukan logam berat dan radionuklid tabii

13


dalam rantai makanan ini akan akhirnya sampai kepada manusia yang memungkinkan pemakannya menghadapi resiko kesihatan. Oleh yang demikian objektif utama kajian ini adalah untuk menentukan aras kandungan logam berat dan radionuklid tabii dalam ikan di tasik bekas lombong serta hubungkaitnya dengan kandungan pada sediment, air dan tumbuhan. Bahan dan kaedah.

a. Kawasan kajian Tiga buah tasik bekas lombong (L1, L2 dan L3) yang dijadikan kawasan kajian terletak di kawasan Puchong (Rajah 1). Ketiga-tiga tasik ini telah ditebusguna dan dijadikan kawasan ternakan akuakultur. b. Sampel kajian. i. Ikan Sampel ikan yang diguna adalah Ikan Keli Kayu (Clarias batrachus), Ikan Patin (Pangasius sutchi), Ikan Tilapia (Oreochromiis mussambics), ikan dari famili Lidae seperti Ikan Toman (Ophiocehalus micropeltes) dan Ikan Haruan (Ophiocehalus striatus), Ikan Tilapia (Oreochromiis Mussambics) atau Ikan Belida (Notopterus notopterus)). Ikan ini ditangkap menggunakan jarring yang dipasang semalaman. ii. Air Sama sebagaimana sampel ikan, sampel air (4L) juga diambil daripada tiga lokasi pada ketiga-tiga tasik. Asid nitrik dititiskan kepada setiap sampel air yang diambil mengelak pertumbuhan mikrob dan menghalang unsur daripada sampel air melekat pada dinding botol plastik yang diguna. Parameter air turut diambil yang meliputi parameter fizikal (suhu, pH, konduktiviti, saliniti dan oksigen terlarut). iii. Tumbuhan Tumbuhan yang diambil bergantung kepada kehadiran pada setiap lokasi. Ianya terdiri dari Eichhornia crassipes, Eragrostis atrovirens, Pennisetum puerperiu, Panicum repen, Pennisetum polystachion, Melampodium divaricatu dan Brachiaria mufica. iv. Sedimen Sedimen diambil menggunakan penceduk plastik dan dimasukkan ke dalam beg plastik yang telah dilabel. c. Perawatan dan analisis sampel i. Ikan. Sampel ikan yang diambil dibasuh menggunakan air suling dan disiang untuk mengasingkan kepala, isi perut, insang dan tisu daging ikan. Setelah dicuci menggunakan air suling, tisu daging ikan yang diketahui beratnya dikeringkan menggunakan ketuhar pada suhu 80°C sehingga beratnya menjadi malar. Sampel kering ini kemudiannya dikisar sekali lagi untuk mendapatkannya butiran halus sekitar 500 µm. Sebanyak 400 mg sampel kemudiannya dicampurkan dengan 3.0 ml asid nitrik, 3.0 ml asid hidroklorik dan 0.5 ml asid peroksida. Campuran dihazam menggunakan kemudahan multigelombang selama dua jam sehingga membentuk larutan jernih. Larutan sampel yang terhasil kemudiannya dituras dan ditambah air suling sehingga isipadu larutan sampel mencecah 100 ml sebelum ditentukan kandungan logamnya berat menggunakan peralatan ICP-MS.

14


Taman P Prima1 2

L1, L2 dan L

RA ii. Air. Sampel air yang

ebanyak 400 mg bperok

menggunakan penatabii dan logam bedipekatkan dan yan Penyediaan sampelyang telah dibersisipadunya mencapa iii. Tumbuhan Sampel tumbuhan iTumbuhan kemuditelah bersihkan dicamenggunakan ketukemudiannya dikisSml) dan asid

L

3

3 Tasik beka

JAH 3.1 Lo

telah diampis membranrat di dalam

utiran halussida (9.0 ml

g tidak dipek

air yang tidihkan mengi 100 ml.

tu dibasuh mannya dibilatatkan. Keshar pada sar menggun

L

s

k

b

s

a

ag

selua

).

utra L

15

lombong.

asi tasik kajian

il itu dibersihkan daripada kotoran dengan cara menapisnya plasma. Sampel air yang digunakan untuk penentuan keradioaktifan kajian ini disediakan di dalam dua bentuk iaitu sampel air yang

kar, daun dan batang) kemudiannya dikeringkan el kering ini itar 500 µm.

eterusn nitrik (3.0 ml), asid hidroklorik (0.5 mp menggunakan kemudahan multigelombang

tkan.

k melalui proses pemekatan ialah dengan cara menuras sampel air unakan membran plasma menggunakan kertas turas sehingga

enggunakan air suling untuk menghilangkan kotoran yang melekat. menggunakan air suling sekali lagi. Berat basah tumbuhan yang uruhan tumbuhan (ahu 105°C sehingga beratnya menjadi malar. Sampkan pengisar untuk mendapatkan butiran halus sek

ya dicampur dengan asid Ca uran dihazamkan


selama dua jam sehingga mem tuk larutan sampel yang terhasil dari proses enghadaman itu kemudiannya dituras dan air suling ditambah sehingga isipadu larutan sampel

mencec iv. Sedimen Sampel edime di toran dengan membuang semua akar tumbuhan dan bendasi lain. t ba dicatatkan. Sampel sedimen kemudiannya dikering an me nak suhu 105ºC sehingga berat menjadi malar. Sampel kering ini eterusnya dikisar untuk mendapatkannya butiran halus sekitar 500 µm.

ebanyak 300 mg butiran halus sedimen dicampurkan dengan asid nitrik (5.0 ml), asid hidroklorik oksida (0.5 ml) dan asid fluorida (3.0 ml). Campuran seterusnya dihazamkan

enggunakan kemudahan multigelombang selama dua jam sehingga membventuk larutan jernih.

itrus Leave) dan larutan Perkin Elmer ure Atomic Spectroscopy Standard.

e. Analisis data

Bagi penentuan kepekatan logam berat yang d berat asal sampe m unit mg/kg ata g/L. Manakala aktiviti radionuklid tabii (Bq/kg) pula boleh ditentukan menggunakan rum

dN = w x NA

Di mana; = Kelimpahan tabii radionuklid tabii di dalam semesta

w = Berat radionuklid tabii di dalam sampel

enunjukkan ifat kealkalian pada air tasik bekas lombong (Riba et al. [4]).

ben jernih. Larutanp

ah 250 ml.

s n itu bersihkan daripada kong Bera sah sedimen yang telah dibersihkank nggu an ketuhar pada

s S(2.0 ml) dan asid permLarutan sampel yang terhasil dari proses penghadaman itu kemudiannya dituras dan air suling ditambah sehingga isipadu larutan sampel mencecah 100 ml. d. Analisis sampel Sampel yang telah disediakan dalam bentuk larutan dianalisis menggunakan Spektrometer Jisim Gandingan Plasma Teraruh (ICP-MS) yang telah dikalibrasi menggunakan piawai (SRM MA-A-2 (TM) Fish Flesh Homogenate), piawai tumbuhan (SRM 1572 CP

, setiap data iperolehi dikira semula kepada

l dan dinyatakan dala u m

us:

λӨ

dt W M

Ө

NA = Nombor Avogadro M = Berat molekul radionuklid tabii W = Berat sampel

Hasil dan perbincangan a. Parameter fizikal Jadual 1 menunjukkan bacaan pelbagai parameter fizikal lombong kajian. Oksigen terlarut yang diukur in situ menunjukkan nilainya berada di antara 7.0 -7.6 mg/l. Kandungan oksigen ini dipengaruhi oleh pelbagai faktor seperti proses pernafasan haiwan akuatik, forosintesis tumbuhan akuatik serta pengoksidaan yang berlaku di bawah permukaan air (Elbering et al. [2]). Air tasik bekas lombong biasanya bersifat asid (Muhamad Samudi Yasir et al. [3]). Sungguhpun begitu hasil kajian ini menunjukkan sebaliknya, iaitu sedikit beralkali. Ini mungkin disebabkan oleh faktor masa, iaitu telah melebihi 15 tahun berhenti beroperasi. Kajian yang dilakukan di Sepanyol juga ms

16


Jadual 1. Pelbagai parameter air dan sedimen tasik

par 3) ameter Tasik 1 (L1) Tasik 2 (L2) Tasik 3 (LOksigen terlarut /L) 7.0 7.4 (mg 7.6Nilai pH ab.sedimen

77.3 6.97

.air

.21 4

7.47 6.80

7.92

Suhu (oC) 30.6 30.0 32,3 K ukti S/c 386 385 278 ond viti (µ m)

Nilai konduktiviti menggamb ka ngan ion ani ng terlarut air tasik. Hasil kajian mendapati nilain ra ada t 278 86 /cm bagi ketiga-tiga tasik. b. Logam bera Logam berat y ditent kan dalam s p sa el ialah mangan, kuprum, zink, arsenik, kad m, stanum o bar me i, p bum onium dan fnium asi ian dap Zn d Cu rupakan lo berat yan ling nya rkan g da tisu daging n dengan masing-masing dalam (0 3.8 /kg) dan (0 .2 g/kg epe tin edua-dua logam ini berbanding l l ungkin disebabkan ua- ya m paka ah da da n en ma di l o kan uk h . S n d da i ajianPapagiannis et al. [5] mendapati hubu ya pat di antara kandungan Zn Cu di dalam kan d oo kto da ko m t Ole ng demikia n da yan kan di m ikan ini m ngk i am sec ida el akanan yan leh i an tersebut. Nilai kepekatan logam erat y g di lehi tidak eleb taha aksim ya dalam Akta Ma n 1 (A iaitu g/ an 100 mg/kg untuk dan Zn. Walau bagaimanapun kandungan pad 2 (0.53 mg adalah 0.05 /kg bih at maksimum yang dibenarkan. Oleh itu bolehlah disimpulkan bahawa tasik tercemar dengan logam b ak kt per t akan menyebabkan peningkatan kepekatan kesemu gam at d am dup akuati i dal ya.

ecara amnya kandungan logam berat dalam air adalah lebih rendah berbanding dengan sedimen dan

ogam berat tertinggi yang dikesan pada tumbuhan adalah mangan iaitu 19.05 ± 8.10 mg/kg di tasik

an yang berada berdekatan berbanding pada keadaan pH rendah. Kandungan Cu i dalam sedimen mungkin meresap melalui air bawah tanah dan akhirnya diambil oleh akar

tumbuhan. Ke an L1. epekatan Hf dan Hg yang tinggi turut dikesan pada ikan dari tasik berkaitan. Oleh yang demikian encemaran logam Hg dan Hf boleh menyebabkan pemekatan dan akhirnya memasuki rantai

arkan ndu kat daµS

n on ya dalamya be da p jula – 3

t

ani, ng u

ium, e ia

lumt m

, zirkp m

ati iu

, antim rkur ha . H l kaj menan me gam g pa ba k te dun lam ika

julat .50 - 1 mg .50 - 2 7 m ). K katan ggi kogam ain m ked

elaiduan eru n seb agian ripa

u itr uta yang ambi leh i unt idup aripa tu, k yang dijalankan oleh ngan ng ra dan i

a zn planu

n di lam e siste asik.k

h ya n, Z n Cu g ter dung dalain d bil

b9 3

ara t langsung m alui m m

kg d

g di ambil o kan pero ini ihi p m um ng dibenarkan

kana 8 kt 281)[a 6] m30 masing-masing Cu Hg a L /kg) mg mele i tak

yangerata lo

ib t aa iviti i dal

lombongan tidak semes tasik terh

inya ber adap yang hi k d amn

Stumbuhan kecuali barium yang mana kandungannya berada dalam julat 7.78 ± 1.80 hingga 27.67 ± 2.25 µg/l (Jadual 2). Barium terdiri daripada logam alkali yang mudah ditemui di dalam perut bumi. Proses perlombongan menyebabkan sebahagian besar logam yang terkandung dalam perut bumi dikeluarkan yang akhirnya menyebabkan kandungannya tinggi pada tasik bekas lombong. LL2, diikuti oleh barium (7.66 ± 0.66 mg/kg) juga di L2. Kajian yang dilakukan di kawasan tasik bekas lombong arang batu di Poland oleh Samecka dan Kempers [7] mendapati kandungan Mn amat tinggi (1142 – 2116 mg/kg) diikuti oleh Zn, Ba dan Pb. Hasil kajian ini didapati tidak mengikut corak tersebut. Ini disebabkan oleh perbezaan jenis mineral yang pernah dilombong. Kandungan Ba juga didapati tertinggi berbanding logam berat lain dalam sedimen, diikuti oleh Pb dan Cu. Terdapat persamaan antara kepekatan Cu dalam sedimen dengan kepekatan Cu dalam tumbuhan di mana kepekatannya adalah paling tinggi di L1, di ikuti oleh L3 dan L2. Corak ini sama dengan nilai pH sedimen (Jadual 1). Ini mungkin disebabkan pada pH tinggi, Cu dalam sedimen dapat diambil oleh tumbuhd

pekatan Hf dan Hg pula adalah paling tinggi di L3 dan diikuti oleh L2 dKppemakanan akuatik.

17


JADUAL 2 Kepekatan logam berat di dalam ikan, sedimen, air dan tumbuhan

Kandungan logam berat dalam sampel (mg/kg) basah atau ug/L (air) L1 L2 L3

Unsur

Ikan Sedimen Air tumbuhan Ikan Sedimen Air tumbuhan Ikan Sedimen Air tumbuhan

Mn

0.0±

0.03 0.85 2.58

8.63 ±

5.56

8 2.2 ±

0.00

3.92 ±

0.07 ±

2.63 ±

0.00

19.05 ±

0.06 ±

0.00

0.00

0.01 0.02 8.10 0.01

Cu 0.50

± 0.02

2.47 ±

1.29

1.00 ±

0.01

5.97 ±

0.48 ±

0.51 0. ±

0.03 ±

0.01

2.28 ±

2.22

1.00 2.49 ±

1.16 ± 33 1.

2.27 1.0 1.00 1.79 0.13 ± 01

± 0.01

Z0.50

10

0.40 ±

0.21

0

0.02

3.81 ±

2.91

0.38 ±

0.01 2.65 0.24

0.65 ±

0.21 0.30 1.03

1.38 ±

0.54 n

± 0.

.88 ±

4.09 ±

0.67

13.5±

0.75 ±

0.51 ±

7.73 ±

As

0.11 ±

0.01

0.34 ±

0.20

2.83 ±

000

0.07 ±

0.01

0.32 ±

0.11

2.25 ±

0.00

0.06 ±

0.01

0.35 ±

0.00

0.00

.29

0.

0.29 0.14

Cd

00

0.00

0.00

0.00

0.00

0.0

0.00

0.07 ±

0.01

0.00

0.00

0.00 0.

0.00 0

Sn 0.00 0.00 0.00 0.00 0.00 0.00 0. 0.00 0.00 0.00 0.00 00 0.00 Sb 0.00 0.00 0.00 00 0.00 0.00 0.00 0. 0.00 0.00 0. 0.00 0.00 00

Ba

00

14.78 ±

5.30

27.7 ±

0.11 ±

45.10 ±

9.26

25.0 ±

7.66 ±

0.13 ±

0.03

13.08 ±

7.78 ±

3.32 ± 19

0.2.25 2.50 0.03

4.52 ±

0.29 0.66 4.20 1.80 1.

H17

01

0.20 ±

0.10 0.0 ±

0.20

0.33 ±

0.10

0.11 ±

0.02 0.

0.00 g

0.±

0.

0.53 0 0.00

0.00 0.00

0.60 ± 0.00 13

c. Radionuklid tabii. Kandungan radionuklid tabii U-238, Th-232 dan K-40 ditunjukkan dalam Jadual 3. Hanya K-40 yang dapat dikesan pada sampel ikan, air, tumbuhan dan sedimen dari ketiga-tiga tasik. Radionuklid U-238 dan Th-232 hanya terdapat pada sampel sedimen.

JADUAL 3. Kandungan radionuklid tabii dalam ikan, air, tumbuhan dan sedimen.

Pb

0.00

6.09 ±

0.73

1.00 ±

0.01

2.26 ±

0.25

0.00

13.55 ±

1.67

1.05 ±

0.01

0.00

0.00

3.57 ±

0.56

0.00

0.68

Zr

0.00

0.33 ±

0.12

0.00

0.00

0.00

0.53 ±

0.20

0.00

0.00

0.12 ±

0.01

0.52 ±

0.16

0.00

0.00

Hf

0.00

0.72 ±

0.06

2.83 ±

0.29

0.00

0.00

1.40 ±

0.31

3.00 ±

0.01

0.00

0.14 ±

0.02

1.65 ±

0.56

0.00

0.00

Kandungan radionuklid tabii (Bq/kg atau Bq/L)

Tasik 1 Tasik 2 Tasik 3 Ikan

K-40 Th-232 U-238

7.78E-02 ± 0.01

0 0

7.34E-02 ± 0.01

0 0

6.52E-02 ± .01

0 0

Air K-40

1.11E-03 ±

Th-232 U-238

0.00 0

36.72

1.07E-03 ± 0.00

0 36.72

1.23E-03 ± 0.00

0 0

Tumbuhan K-40 Th-232 U-238

0.09 ± 0.05 0 0

1.12E-03 ± 0.00 0 0

0.10 ± 0.04 0 0

Sedimen K-40 Th-232

1.57E-04 ± 4.48E-05

30.76 ± 2.71

4.24E-04 ± 1.47E-04

35.

9.44E-05 ± 5.40E-06

U-238 18.86 ± 2.60 34 ± 0.27

26.32 ± 3.01 34.06 ± 11.85 9.37 ± 2.30

18


Terdapat dua laluan utama yang membolehkan ikan di tasik bekas lombong dicemari oleh K-40, iaitu elalui deposisi permukaan ataupun melalui rantai pemakanan ikan tersebut. Deposisi permukaan

ajian ini menunjukkan walaupun ketiga-tiga radionuklid rdapat pada sediment, hanya K-40 yang dapat dikesan pada tumbuhan dan ikan. unsur K-40, Th-232 dan U-238 dalam ekosistem akuatik boleh berlaku melalui ampaian

e

padolehuns

pul

t nggi berbanding

danmungkin terjadi kerana faktor kedudukan tropik ikan yang tinggi menyebabkan berlaku pemekatan K-

0 dalam jumlah yang banyak.

Kes

mbong mengandungi pelbagai logam

beradari mbong ini berpotensi

Pen

per

ujukan

Amran Ab Majid, Muhamad Samudi Yasir, Redzuwan Yahaya. 2004. “Taboran Radionuklid Tabii (NORM) dan Kaitannya dengan Aktiviti Pembangunan di Negeri Selangor”. Dalam: Indicator of Sustainable Development: Assessing Changes in Environmental Conditions. A. Latiff et al. (ed), Institute For Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, ISBN 983-9444-58-1, 213 – 225.

. Elbering B., Knudsen K.L, Kristensen P.H dan Asmund G., 2004. “Appliying foramineral stratigraphy contaminationand mining impact in a fiord in West Greenland”. Marine Enviromental Research 55 3: 235-256.

. Muhamad Samudi Yasir, Ismail Bahari, Sahibin A.R., Dahlia Suriati Abd Rahim and Halim Abd Rahman, 2001. “The Concentration of Natural Radiobuclides and Heavy Metals in Soils From A Tin-Mining and Its Surrounding Area”. J. Sains Nuklear Malaysia, 19: 50 – 56.

. Riba I., Conradi M., Forja J.M. dan Delvalls T.A. 2004. “Sediment Quality in the Guadalquivir Estury: Lethal Effect Associated with the Azhalcollar Mining Spil”. Marine Pollution Bulletin. 48 1:144-152.

mboleh berlaku apabila terdapat pemindahan unsur kalium daripada komponen ekosistem tasik seperti sedimen dan tumbuhan. Aktiviti perlombongan dijangka meningkatkan kandungan pelbagai adionuklid tabii di kawasan sekitarnya. Kr

tersebut teenyebaranP

pep jal yang seterusnya membabitkan komponen akuatik lain seperti plankton, herbivor, karnivor serta omnivor yang terdapat dalam sistem akuatik tersebut. Ketiadaan U-238 dan Th-232 dikesan

a tumbuhan adalah disebabkan unsur tersebut diikat kuat oleh komposisi tanah dan sukar di ambil tumbuhan. Selain daripada itu, tumbuhan juga tidak mengambil uranium dan thorium sebagai

ur nutrien. Kajian sebelum ini mendapati kandungan radionuklid tabii U-238 dan Th-232 dalam sampel tanah di kawasan lombong aktif adalah masing-masing 3.75 Bq/kg dan 10.51 Bq/kg (Muhamad Samudi Yasir et al.[8]), manakala kandungan dalam sistem air kawasan lombong aktif

a adalah antara 26.3 – 36.2 Bq/L (Th-232) dan 26.8 – 35.4 Bq/L (U-238) (Ismail et al. [9]. Oleh g demikian kandungan radionuklid tabii yan dalam semua sampel yang di ambil adalah lebih rendah

dari hasil kajian sebelumnya.

iviti U-238 dan Th-232 bagi sedimen di L1, L2 dan L3 adalah relatif lebih tiAkaktivitinya di dalam tisu daging ikan, air dan tumbuhan. Tetapi aktiviti K-40 bagi sedimen di L1, L2

L3 adalah relatif lebih rendah berbanding aktivitinya di dalam tisu daging ikan. Fenomena ini

4

impulan

Hasil kajian ini mendapati walaupun ekosistem tasik bekas loberat dan radionuklid tabii, kandungannya kebanyakan logam berat dalam ikan adalah rendah dan

da di bawah aras maksimum yang dibenarkan dalam Akta Makanan (1983). Oleh yang demikian sudut pencemaran logam berat dan radionuklid tabii kawasan tasik bekas lo

untuk dimajukan sebagai kawasan ternakan akuakultur.

ghargaan

Penulis merakamkan ucapan terima kasih kepada Universiti Kebangsaan Malaysia di atas untukan kewangan yang disediakan.

R 1.

2

3

4

19


5. Fou ental International. 30 (3) :257-36

6. Akta Makanan 1983. MDC Kuala Lumpur. 7. er,

sediments and aquatic macrophytes of an mer open cut brown coal mines) differing in st Environment International

8. Muhamad S “Kandungan Radionuklid Tabii ar Kawasan Industri Perlombongan Di Dengkil Selangor”. Proceeding of The 6th ITB-UKM Joint Seminar on Chemistry, 17 – 18 May 58.

9. B. Ismail, M.S. Yasi cal Environmental Risk Associated with Di ocessing in Malaysia”. Pakistan Journal of Biological

Papagiannis I, Kagalov I., Leonardos J., Petridis D. dan Kalfakou V. 2004. “Copper and Zink inr Freshwater Fish Species from Lake Pamvotis (Greece)”. Journal of Envirom

2. ,

Samecka C. dan Kempers. 2004. “Consentrations of heavy metal and plant nutrients in watthropogenic lakes (for

age of acidification”. . 281 :87-98 amudi Yasir, Amran Ab Majid dan Redzuwan Yahaya, 2005.

Dalam Sampel Amang, Tanah dan Air di Sekit

, Bali Indonesia. ISBN: 983-29766-38-7653 - 6r, Y. Redzuwan and A.M. Amran, 2003. “Radiologifferent Water Management System in Amang Pr

Science. 6: 1544 – 1547.

20


CHARACTERIZATION OF NOVEL ORGANOTIN(IV) COMPLEXES WITH O, N, O – DONOR LIGAND DERIVED FROM CARBOHYDRAZIDE: X-RAY CRYSTAL

STRUCTURE OF [Ph2Sn(H2CBS)]

Y. Z. Liew 1*, M. A. Affan 1, F 1 2asihuddin B. Ahmad , Mustaffa B. Shamsuddin and Bohari M. Yamin 3

1Resource Chemistry, Faculty of Resource Science and Technology

Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia

2Department of Chemistry, Faculty of Science,

Universiti Teknologi Malaysia, 81310 UTM Skudai Johor Darul Takzim, Malaysia

3School of Chemical Sciences and Food Technology Universiti Kebangsaan Malaysia, 3600 Bangi, Selangor, Malaysia

Abstract An interesting series of new organotin(IV) complexes has been synthesized by the reaction of RnSnCl4-n with potentially O, N, O – tridentate carbohydrazone ligand derived from carbohydrazide. Five new organotin(IV) complexes of carbohydrazide-bis(salicylaldehyde) ligand [H4CBS, (1)] with RnSnCl4-n (n = 1, 2) have been synthesized in the presence of base and refluxing in 1:2:1 molar ratio (metal:base:ligand). All complexes (2-6) have been characterized by different physico-chemical techniques like molar conductivity measurements, elemental analysis, UV-Visible, IR and 1H NMR

mplexes (2-6) are non electrolytic in nature. Among them, diphenyltin(IV) omplex (4) is also characterized by X-ray crystallography diffraction analyses. In the solid state, the arbohydrazone ligand (1) exist as the keto tautomer but in solution in the presence of base and

organotin(IV) chloride(s), it converted to the enol automer and coordinated to the tin atom in its eprotonated enolate form. X-ray crystallographic analysis shows that the diphenyltin(IV) complex, h2Sn(H2CBS)] (4), is five-coordinate and has a distorted trigonal-bipyramidal geometry with the

ligand coordinated to the tin(IV) as a tridentate dinegative fashion through its phenolic-O, enolic-O and imine-N atoms. The general bond length o < phenolato < enolato. The Sn-O (enolato) bond is longer than Sn-O (phenolato) bond by ~0.095 Å and is identical with Sn-O (carboxylate) bond. The crystal of [Ph2Sn(H2CBS)] (4) is triclinic with space group P-1 with a=8.514(2)Å,

4)Å, α=105.169(4)°, β=107.639(4)°, γ=96.232(4)°, V=1226.5(6) Å3, Z=1 Mg/m3. The IR, UV and 1H NMR data are consistent with all the organotin(IV)

erivatives having similar geometry.

eywords

4

spectral studies. All cocc

td[P

order is: ox

b=12.505(3)Å, c=12.794(and Dcalc=1.541d K : Carbohydrazone ligand; Organotin(IV) compounds; Crystal structure. Corresponding author: Tel.: 6082-679235; fax: 6082-672275 E-mail address: [email protected]

Introduction

e to the presence of several Hydrazides and hydrazones have interesting ligational properties dupotential coordination sites. The chemistry of carbohydrazide compounds has been studied by Swamy and Siddalingaiah [1]. Variety of metal complexes of symmetrical dihydrazones derived from thiocarbohydrazides have been synthesized and their stereochemistry have been reported in the literatures [2-3] and potentially useful biological activities [3]. However, the coordination chemistry of the corresponding carbohydrazide derivatives is less explored [4]. Complexes of the carbohydrazide with non-transition metal ions such as organotin(IV) have not received as much

21


attention. In view of the importance of tin compounds in medicinal chemistry and biotechnology [5] and as part of our on going work on tin-hydrazones [6-7], here we report about the synthesis and characterization of the carbohydrazide-bis(salicylaldehyde) ligand (Scheme 1) and of its organotin(IV) complexes (Scheme 2) and together with the X-ray crystal structure of diphenyltin(IV) omplexes [Ph2Sn(H2CBS)] (4). c

H

O

CN

H2N NH2

N

H

H

O C

HO

Carbohydrazide

+

Salicylaldehyde

2

abs. ethanol

2H2O

Keto form

Scheme 1

Enol form

eter.

Experimental Synthesis Chemicals were obtained from Fluka and Aldrich and were used without further pwere analytical grade and purified by standard methods [8]. The C, H, N elemperformed on a Carlo Erba model EA 1108 analyser. Infrared spectra were recordeShimadzu 8201 PC Fourier-Transform Spectrometer. 1H NMR spectra were recsolution on a Bruker 300 FT-NMR spectrophotometer. Electronic spectra w

himadzu 2401 PC UV-Visible spectrophotomS

22

+

urification. Solvents ental analyses were d as KBr disc using orded in DMSO-d6 ere recorded on a


Carbohydrazide-bis(salicylaldehyde) ligand (H CBS) [C H N O ] (1)

. p. = 178-180 °C. Found: C, 59.20; H, 4.59; N, 18.40%. Calc. for C15H14N4O3: C, 59.21; H, 4.61; DMF): 262, 292, 328. IR (νmaxcm-1 (KBr): 1681(-C=O), 1616 (C=N)+(C=C),

272 (C–O, phenolic), 946 (N–N). 1H NMR (300 MHz, DMSO-d6): δ 10.86 (br, OH), δ 8.44 (s,

ried in vacuo over P2O5 overnight. Yield = 69.51%. M. p. = 218-220 °C. Found: C, 45.91; H, 4.03; , 12.56%. Calc. for C15H12N4O3Me2Sn: C, 45.88; H, 4.05; N, 12.59%. λmax (nm) (DMF): 266, 343,

: 1604 (C=N)+(C=C), 1318 (C–O, phenolic), 960 (N–N), 608 (Sn–C), 566 n–O), 470 (Sn–N). H NMR (300 MHz, DMSO-d6): δ 11.41 (br, OH), δ 10.89 (s, NH) δ 8.14 &

max (nm) (DMF): 67, 340, 396. IR (νmaxcm (KBr): 1604 (C=N)+(C=C), 1323 (C–O, phenolic), 952 (N–N), 590 (Sn–), 560 (Sn–O), 440 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.45 (br, OH), δ 11.05 (s, NH) δ

8.15 & 8.41 (s, N=CH)), δ 6.65–7.89 (m, aromatic-H), δ 0.79 (t, 6H, (-CH3) of butyltin), δ 1.18 (m, H2-Sn).

Ph2Sn(H2C (4) Complex y to complex (2), using diphenylt ) dichloride (0.002 mole, 0.688 g) i dichloride. Single crystals suitable for X-ray diffraction studies were obta of dichloromethane-petroleum ether (40-60 °C) solution (1:1).

ield = 210 °C. Found: C, 56.65; H, 3.88; N, 9.87%. Calc. for 15H12N4O3Ph2Sn: C, 56.69; H, 3.87; N, 9.85%. λmax (nm) (DMF): 266, 342, 398. IR (νmaxcm-1 (KBr):

–N), 600 (Sn–C), 520 (Sn–O), 460 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.48 (br, OH), δ 11.15 (s, NH) δ 8.17 & 8.38 (s, N=CH)), δ 6.70–7.62 (m, aromatic and Sn-C6H5 protons). MeSnCl(H2CBS) [MeSnCl(C15H12N4O3)] (5) The procedure described above for (2) was followed for the preparation of (5), with methyltin(IV) trichloride being used instead of dimethyltin(IV) dichloride and the refluxing time for this preparation

4 15 14 4 3 A mixture of carbohydrazide (0.005 mole, 0.450 g) and salicylaldehyde (0.0010 mole, 1.221 g) in absolute ethanol (30 mL) were heated under reflux for 3-4 hours. The reaction mixture was allowed to cool down to room temperature for half an hour. Then the white precipitate was filtered off and washed several times using absolute ethanol. The crystalline white solid obtained was purified by recrystallization from hot absolute ethanol and dried in vacuo over P2O5 overnight. Yield = 70.05%. MN, 18.42%. λmax (nm) (1N=CH), δ 7.69 (br, CONH), δ 6.62–7.27 (m, aromatic-H). Me2Sn(H2CBS) [Me2Sn(C15H12N4O3)] (2) Carbohydrazide-bis(salicylaldehyde) ligand (1) (0.002 mole, 0.596 g) was dissolved in hot absolute methanol (20 mL) under nitrogen atmosphere with potassium hydroxide (0.0042 mole, 0.236 g) previously dissolved in methanol (10 mL). The colour of the solution changed from off-white to yellow. The resulting mixture was refluxed for one hour and a solution of Me2SnCl2 (0.002 mole, 0.439 g) in methanol (10 mL) was added dropwise to the potassium salt of ligand solution, the color of the solution became darker. The resulting solution was refluxed for four hours and allowed to cool. The precipitated potassium chloride (KCl) was removed by filtration and the filtrate was evaporated to obtain the yellow solid. The yellow micro-crystals were filtered off and washed with hexane and dN398. IR (νmaxcm-1 (KBr)

1(S8.43 (s, N=CH)), δ 6.63–7.93 (m, aromatic-H). δ 0.68 (s, Sn-CH3). Bu2Sn(H2CBS) [Bu2Sn(C15H12N4O3)] (3) Complex (3) was synthesized in a similar way as in (2), using dibutyltin(IV) dichloride (0.002 mole, 0.688 g) instead of dimethyltin(IV) dichloride. Yield = 68.51%. M. p. = 225-227 °C. Found: C, 52.00; H, 6.03; N, 10.55%. Calc. for C15H12N4O3Bu2Sn: C, 52.02; H, 6.02; N, 10.55%. λ

-12C

4H, (-CH2) of butyltin), δ 1.26-1.45 (m, 4H, (-CH2) of butyltin) δ 1.55-1.64 (m, 4H, -C

BS) [Ph2Sn(C15H12N4O3)]

(4) was prepared similarl)

in(IVnstead of dimethyltin(IV

wined by slo evaporation64.33%. M. p. = 208-Y

C1600 (C=N)+(C=C), 1325 (C–O, phenolic), 960 (N

23


was 2-3 hours. Yield = 65.46%. M. p. = 205-206 °C. Found: C, 41.19; H, 3.25; N, 12.05 %. Calc. for C15H12N4O3MeSnCl: C, 41.23; H, 3.22; N, 12.02%. λmax (nm) (DMF): 267, 341, 398. IR (νmaxcm-1 (KBr): 1610 (C=N)+(C=C), 1340 (C–O, phenolic), 952 (N–N), 590 (Sn–C), 560 (Sn–O), 472 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.42 (br, OH), δ 10.96 (s, NH) δ 8.14 & 8.44 (s, N=CH)), δ 6.64–7.90 (m, aromatic-H). δ 1.14 (s, Sn-CH3). PhSnCl(H2CBS) [PhSnCl(C15H12N4O3)] (6) The proced (5) was followed for the preparation of (6), with phenyltin(IV) trichloride being used instead of methyltin(IV) trichloride. Yield = 64.23%. M. p. = 213-215 °C. Found: C, 49.10; H, 3.63; N, 10.22 %. Calc. for C15H12N4O3PhSnCl: C, 49.15; H, 3.66; N, 10.25%.λmax (nm) (DMF): 268, 340, 399. IR (ν axcm-1 (KBr): 1608 (C=N)+(C=C), 1330 (C–O, phenolic), 956 (N–N), 615 (Sn–C), 520 (Sn–O), 451 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.44 (br, OH), δ 11.10 (s, NH) δ 8.18 & 8.3 2 m, aromatic and Sn-C6H5 protons).

-ray Crystallography

Yellow single-crystal of (4) (size 0.46 x 0.17 was grown from dichloromethane-petroleum her (40-60 °C) mixture at the room temperature. The measurements were performed at 273 (2) K on iemen SMART CCD diffraction using graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). rientation matrix and unit cell parameters were obtained from the setting angles of 25-centered

onoclinic, space group P2(1)/c with a = 8.514(2), b = 12.505(3), c = , β = 107.639(4)°, γ = 96.232(4)°, V = 1226.5(6) A3, Z = 1, Dcalc = 1.541

3 -1

ation reaction of eme 1). Five new

rganotin(IV) com hydrazide is(salicy 1) have been synthesized by dir opriate organotin(I ith the ligand in the presence of a base (Sch 2). I is added to the reaction mixture in order to force the deprotonation e liga uctanc ohm-1cm2 mol-1) (see Table 1) indicating non- trolyt notin(I 10].

nce values for organotin(IV) complexes of ligand (1)

ure described above for

m

9 (s, N=CH)), δ 6.72–7.6 (

X

x 0.09 mm) etSOreflection. The crystals are m

2.794(4) Å, α = 105.169(4)°1Mg/m , µ = 1.078 mm . The diffraction intensities were collected by ω scans (1.7 to 27.0°). A total of 13623 / 5308 reflections were collected (-10< =h< =10, -15< =k< =15, -16< =l< =16). The structure was solved using direct methods and refined using the full-matrix least-square method on F obs2 using the SHELXTL [9] software package. All non-H atoms were anisotropically refined. The hydrogen atoms were located in a difference Fourier map and then were fixed geometrically and treated as riding atom on the parent C atoms, with C-H distances = 0.97 Å.

esults and discussion R The carbohydrazone ligand [H4CBS, (1)] was synthesized by the condensarbohydrazide with salicylaldehyde in a 1: 2 ratio in absolute ethanol (Schc

o plexes (2-6) of carbo -bect re ction of the appr

laldehyde) ligand (V) halide(sa ) w

eme of th

n all the c ses, a base nd. The low molar cond

ae values (10-40

elec ic nature f r all the orgao V) complexes [

Table 1. Molar conducta

Compound Molar conductance, Λm (ohm-1 cm 2 mol -1) [Me2Sn(H2CBS)] (2) 10 [Bu2Sn(H2CBS)] (3) 23 [Ph2Sn(H2CBS)] (4) 29 [MeSnCl(H2CBS)] (5) 40 [PhSnCl(H2CBS)] (6) 35

24

Prosiding Simposium Kimia Analisis Malaysia Ke-18, Johor Bahru Prosiding Simposium Kimia Analisis Malaysia Ke-18, Johor Bahru

abs. MeOH

Electronic absoption spec

The UV-Vis electronic sptemperature in DMF (1Carbohydrazone ligand (1bands were attributed to bthe chelation. The third ba343 nm and at 396-399 nThe high wavelength baninvolving the tin atom [11 Table 2. The λmax (nm) pe

(1(2(3(4(5(6

RnSnCl4-n + Ligand [H4CBS, (1)] + 2KOH

25

O

NN N

CC C

OH

H

O

N

Sn

R R

HH

NC

OH

HH

Scheme 2

R = M

R = Me, Bu and Ph

tra

Compounds

ectra of ligand (1) and its org0-4 M) solutions over 200) exhibited three main bands enzene π – π* and imino (C=Nnd is assigned to n – π* transim regions showed the metal-lds in the region 396-399 nm c].

aks of ligand (1) and its organ

) H4CBS ) [Me2Sn(H2CBS)] ) [Bu2Sn(H2CBS)] ) [Ph2Sn(H2CBS)] ) [MeSnCl(H2CBS)] ) [PhSnCl(H2CBS)]

25

OR

O

NN

CC

O

N

Sn

R Cl

H

e and Ph

)

anotin(IV) complexes (2-6) measured at room – 800 nm range are given in Table 2. at 262, 292 and 328 nm. The first and second ) π – π* transition, which were not affected by

tion. The appearance of two new bands at 266-igand coordination in all the complexes (2-6). an be attributed to a charge transfer transition

otin(IV) complexes (2-6).

λmax (nm, 262 328, 292

8, 343, 266 39398, 342, 266

396, 340, 267 341, 267 398, , 340, 268 399


Infrared spectra

R data for the ligand (1) and its all organotin(IV) co esis The IR spectra of the complexes (2-6), the di of the ν(C=O) band indicating

he amide group into C-OH enolic form through the amide-imidol tautomerism process on of the functional grou coordination to tin atom [12]. The

he complexes (2-6) appeared as a str in the region 1600–1610 cm-1, is ted towards lower frequencies with respect to that of the free ligand (1620 cm-1),

f the azomethine nitrogen 2]. This is also (Sn–N) band at 440–472 cm-1 in the lexes (2-6). The

N–N) band observed at 950 cm e ligand (1) is shifted in the higher gion at 952–962 cm in the complexes (2-6) further supporting that azomethine nitrogen is

oordinated to Sn(IV) ion [11]. The high intensity band observed at 1272 cm-1 in the ligand (1) ttribute

erimental section. The 1H NMR spectrum of ligand (1) is characterized by four signals at 10.86, 8.44, 7.69 and 6.62–7.27 ppm, which are assigned to the protons associated with –OH, –N=CH, –CONH and aromatic ring protons, respectively. In 1H NMR spectra of organotin(IV) complexes (2-6), azomethine N=CH signal is splited into two signals at 8.14-8.17 and 8.38-8.43 ppm. This indicates that only one of the azomethine nitrogen in ligand (1) could be bonded to the Sn(IV) ion in the complexes (2-6), another one HC=N group could be free in the complexes (2-6). This evidence is confirmed from X-ray crystallographic analyses. The disappearance of the signal due to –CONH proton in the complexes (2-6) indicated the enolization of the form of the ligand (1) in the complexes (2-6) [6]. The new signal at 10.89-11.15 ppm in the complexes (2-6) is due to the free NH group of ligand (1) which is not involved in the coordination to tin(IV) in the complexes (2-6). A signal appeared at 11.41-11.48 ppm, which is indicated that phenolic proton present in the complexes (2-6). The sharp signal attributed to methyl group attached to tin atom is appeared as a singlet at 0.68 ppm in the dimethyltin(IV) complex (2). Another sharp resonance signal attributed to methyl group attached to tin(IV) atom is appeared as a singlet at 1.14 ppm in methyltin(IV) complex (5). In the complex (3), a multiplet in the region 0.79-1.64 ppm is assigned to the butyl group attached to the tin(IV) atom. Complexes (4 and 6) showed a multiplet in the region 6.70-7.62 ppm, which may be assigned to aromatic ring protons and Sn-Ph protons, respectively. The signals could not properly assigned due to overlap of corresponding signals of Ph-Sn and aromatic ring protons. Crystal structure of [Ph2

e-nd

ement for compound [Ph2Sn(H2CBS)] (4) are summarized in Table 3. The selected bond angles f lecule (4) are given Table 4. The crystal structure of

S)] (4) reveals the tin(IV) atom has a five coordination geom istorted trigonal-arrangemen atom lies in lane and fo embered and six elate ring with the ligand. Thus the l groups and an imine nitrogen take the

osition, whil en atoms, O(1 take up the a around the Sn(1)

The I mplexes (2-6) are described in the synthsection. sappearanceenolization of tand also indicating deprotonati p duringν(C=N) band in t ong bandconsiderably shifconfirming the coordination o to organotin(IV) moiety [1apparent from the ν IR spectra of all the comphydrazinic stretching ν(

-1

-1 for threca d due to phenolic ν(C–O), appears as a medium band at 1319-1340 cm-1 in the IR spectra of all the complexes (2-6). These observations favour the formation of Sn–O bond via deprotonation. The medium and weak bands observed at 590-651, 520–560 and 440–472 cm-1 in the IR spectra of all the complexes (2-6) are attributable to the ν(Sn–C), ν(Sn–O) and ν(Sn–N) vibration bands respectively, indicating coordination of the free ligand to the central Sn(IV) atom via deprotonated enolic oxygen and azomethine nitrogen in the complexes (2-6). 1H NMR spectra The 1H NMR data for the ligand (1) and its all complexes (2-6) are presented in the exp

Sn(H2CBS)] (4) The X-ray structural investigation of [Ph2Sn(H2CBS)] (4) (Figure 1) revealed that the carbohydrazid

is(salicylaldehyde) ligand [H4CBS, 1] is O,N,O-coordinated in complex (4). The crystal data abstructure refindistances and or the mo in [Ph Sn(H CB2 2 etry in a dbipyramidal membered ch

t. The Sn(1) the ligand p rm five m two pheny

equatorial p e the oxyg ) and O(2), xial sites atom.

26


Table 3. Crystal data and the structure refinement for the complex [Ph2Sn(H2CBS)] (4)

(Å ) calc (m

C27H22N4O3Sn

Formula Formula weight Crystal system Space group Z a (Å) b (Å) c (Å) α (°) β (°) γ (°)

3VD g m-3) Absorption coefficient (mm-1) Temperature (K) Wavelength (Å) Final R indices [I>2sigma(I)] R indices (all data) Goodness-of-fit on F^2

1.541 1.078 273(2) 0.71073 R

569.18 Triclinic P-1 1 8.514(2) 12.505(3) 12.794(4)

) 105.169(4107.639(4) 96.232(4) 1226.5(6)

1 = 0.0337, wR2 = 0.0805 R1 = 0.0380, wR2 = 0.0829 1.135

The distorted trigonal-bipyramidal arrangement is a result of the strain imposed by the tridentate ligand, and from the constraints imposed by the six membered ring, Sn(1)-/N(1)-C(7)-C(6)-C(5)-/O(1) and five membered ring Sn(1)-/N(1)-N(2)-C(8)-O(2). The trigonal-biypramidal geometry

complex (4) is distorted as indicated by the bond angles of 157.08(8)° for O(1)-Sn(1)-O(2) and the indeviation from 90° of the angles O(1)-Sn(1)-N(1) (84.96(8)°) and O(2)-Sn(1)-N(1) (72.89(8)°). The um of the angles O(1)–Sn(1)–N(1), 84.96(8)° and O(2)–Sn(1)–N(1), 72.89(8)° is 157.85°, and it is s

almost the same with the angle O(1)–Sn(1)–O(2), 157.08(8)°, so that the atoms Sn(1), N(1), O(1) and O(3) are co-planer. The sum of the angles C(21)-Sn(1)-N(1), C(22)-Sn(1)-N(1) and C(21)– Sn(1)–C(22) is 358.62°, thus the atoms Sn(1), N(1), C(19) and C(23) are almost in the same plane.

Figure 1. Molecular structure of [Ph2Sn(H2CBS)] (4). Thermal ellipsoids at the 50% level.

27


Tab . Selected bond lengths (Å) and angles (°) of diphenyltin(IV) complex [Phle 4 Bond le

2Sn(H2CBS)] (4)

ngths Sn(1)-O(1) 2.0482(19) Sn(1)-N(1) 2.162(2) Sn(1)-O(2) 2.1430(19) Sn(1)-C(21) 2.112(3) Sn( C(5) 1.340(3) 1)-C(22) 2.117(3) O(1)-O(2)-C(8) 1.282(3) N(1)-C(7) 1.301(3) N(1)-N(2) 1.376(3) N(2)-C(8) 1.310(4) N(3)-N(4) 1.362(3) N(3)-C(8) 1.361(3) C(6)-C(7) 1.424(4) N(4)-C(9) 1.272(4) C(9)-C(10) 1.456(4) Bond angles O(1)-Sn(1)-C(21) 97.52(9) O(1)-Sn(1)-C(22) 99.19(10) C(21)-Sn(1)-C(22) 120.45(9) O(1)-Sn(1)-O(2) 157.08(8) C(21)-Sn(1)-O(2) 91.16(9) C(22)-Sn(1)-O(2) 94.52(9) O(1)-Sn(1)-N(1) 84.96(8) C(21)-Sn(1)-N(1) 126.43(9) C(22)-Sn(1)-N(1) 111.74(9) O(2)-Sn(1)-N(1) 72.89(8) C(5)-O(1)-Sn(1) 127.47(18) C(8)-O(2)-Sn(1) 112.67(17) C(7)-N(1)-Sn(1) 125.69(19) N(2)-N(1)-Sn(1) 116.73(16) C(7)- 1)-N(2) 117.4(2) C(9)-N(4)-N(3) 119.4(2) N(O(1)-C(5)-C(6) 122.7(2 C(5)-C(6)-C(7) 125.2(2) N(1)-C(7)-C(6) 117.0(3) O(2)-C(8)-N(2) 126.4(2)

The asymmetry of H4CBS ligand is strongly reflected in the Sn-O distances. In the complex

consequSalAp/s

t 2.162(2OC10H6 )Ph]

(O)N2Cless tha er Waals radii of tin and nitrogen, 3.75 Å [18]. Due to the involvement

compar

he synthesis and physical properties of a new series of organotin(IV) compounds with arbohydrazone ligand (1) have been described. The ligand behaved as a tridentate dinegative fashion wards to tin(IV). The complexes (2-6) are monometallic. The coordination around the tin(IV) ion is

established by means of single crystal X-ray diffraction analysis on [Ph2Sn(H2CBS)] (4). Acknowledgement The authors are very grateful to Universiti Malaysia Sarawak (UNIMAS), for the financial support (Grant # -01(101)/453/2004(190). The authors also would like to thank the School of Chemistry Sciences and Food Technology, Universiti Kebangsaan Malaysia (UKM), for the CHN analyses and also X-ray single crystal determination. We would also like to thank the Ibnu Sina Institute, UTM, for the help in obtaining the 1H NMR spectra.

(4), the Sn(1)-O(2) bond, 2.1430(19)Å, is longer than the Sn(1)-O(1) bond, 2.0482(19)Å. This is a ence of O(2) being a carbonyl and O(1) being bound to a benzene ring. In Ph2SnSalAp (where alicylideneamino-o-hydroxybenzene), the Sn-C bonds are 2.118(5) Å and 2.111(5) Å [13], is

almos similar with the Sn-C bonds found in complex (4), 2.112(3) Å and 2.117(3) Å. The Sn–N, ) Å bond of the compound (4) is a little longer than that of the compound [Ph2Sn(2-CHNCH2COO)]SnPh2Cl2 2.136 Å [14] and Ph2Sn[Ph(O)C=CH-C(Me)=N-N=C(O

2.145(3) [15], but shorter than that of [SnMe2(Salop)] 2.221(3) Å [16] and Ph2Sn[4-NC5H4–(CH3)CO2](H2O)2 .CH2Cl2 .H2O, 2.288(7) Å and 2.282(7) Å [17], and it is considerably

n the sum of the van dof N(1) atom in tin binding, the bond length of N(1)-C(7) is significantly increased to 1.301(3) Å as

ed with the imine function N(4)-C(9) (1.272(4) Å) which is having a double bond character.

Conclusions

Tcto

28


R [1] Swamy, H. M. V. on some lanthanides(III)

complexes of o-, m- and Ind. J. Chem. 39A. 1150-

[2] comple N,N′-bis(4-pyridylcarboxyl)-2,6-pyridi hem. Comm. 8. 379-381.

[3] Niasari, M. S., Mostafa, R. A. (2004) “Tem condensation reactions of formaldehyde with amines and 2, 3- butanedihydrazone: preparation and properties of nickel(II) complexes of

Mustaffa, B. S., Bohari, M. Y. (2003) “In: Analytical Chemistry” eds. B. A. Zaini, B. A. Fasihuddin, B. J. Ismail, S. Lau, and M.

IS, Sarawak, Malaysia. 214-221. Affan, M. A. (1999) “

3. 2569-2578. lano, E. E. (1994) “Diorganotin(IV)

a 216. 169-172. 3] Yearwood, B., Parkin, S., Atwood, D. A. (2002) “Synthesis and characterization of organotin

” Inorg. Chim. Acta 333. 124-131. ., Goh, N. K., Chia, L. S., Koh, L. L. (1997) “Molecular adducts of

eferences

, Siddalingaiah, A. H. M. (2000) “Studies p- chloro substituted diphenylcarbazones”

1156. Wang, C. X., Du, S. X., Li, Y. H., Wu, . J. (2005) “A novel 3D cadmium coordinationY

x [Cd(H2L) · 1.5H2O]n with strong photoluminescent property: (H4L = ne dicarbohydrazide) ” Inorg. C

plate

18-membered decaaza macrocycles” Polyhedron 203. 1325-1331. [4] Warad, D. U., Satish, C. D., Kulkarru, V. H. (2000) “Synthesis, structure and reactivity of

Zn(II), V(II), Co(II), Ni(II) and Cu(II) complexes derived from carbohydrazide Schiff base ligands” Ind. J. Chem. 39A. 415-420.

[5] Tergioglu, N., Gurso, N. (2003) “Synthesis and anticancer evaluation of some new hydrazone derivatives of 2,6-dimethylimidazo[2,1-b][1,3,4]thiadiazole-5-carbohydrazide” Euro. J. Med. Chem. 38. 781-786.

[6] Affan, M. A., Fasihuddin,B. A., Ramli, B. H.

Murtedza, Published by UNIMAS & ANAL[7] Novel complexes of molybdenum carbonyls, organotin(IV) and

lanthanide(III) ions with hydrazones and azines” PhD Thesis, Universiti Teknologi Malaysia. [8] Armarego, W. L. F., Perrin, D. D. (1998) “Purification of Laboratory Chemicals” 4th edition,

Butterworth Heinemann, Oxford, USA. [9] Sheldrick, G. M. (1997) “SHELXTL V5.1. Software Reference Manual. Bruker AXS” Inc.,

Madison, WI, USA. [10] Geary, W. G. (1971) “The use of conductivity measurement in organic solvent for the

characterization of coordination compound” Coord. Chem. Rev. 7. 81-122. [11] Khalil, T. E., Labib, L., Iskandar, M. F. (1994) “Organotin(IV) complex with tridentate

ligand” Polyhedron 1[12] Casas, J. S., Sanchez, A., Sordo, J., Lopez, V. A., Castel

derivatives of salicylaldehyde thiosemicarbazone” Inorg. Chim. Act[1

Schiff base chelates14] Khoo, L. E., Xu, Y[

diorganotin dichloride with N- (2-oxidoarylideneaminoacidato) diorganotin(IV) complexes. Crystal structure of [Ph2Sn(2-OC10H6Ch=NCH2COO)]SnPh2Cl2” Polyhedron 16. 573-576.

[15] Dey, K. D., Lycka, A., Mitra, S., Rosair, G. M. (2004) “Simplified synthesis, 1H, 13C, 15N, 119Sn NMR spectra and X-ray structures of diorganotin(IV) complexes containing the 4-phenyl-2,4 butanedionebenzoylhydrazone(2−) ligand” J. Organomet. Chem. 689. 88-95.

[16] Hill, H. A. O., Morallee, K. G., Mestroni, G., Costa, G. (1968) “Electronic transmission in some organometallic derivatives of cobalt(III) BAE and SALEN complexes” J. Organomet. Chem. 11. 167-173.

[17] Yin, H. D., Hong, M., Wang, Q. B., Xue, S. C., Wang, D. Q. (2005) “Synthesis and structural characterization of diorganotin(IV) esters with pyruvic acid isonicotinyl hydrazone and pyruvic acid salicylhydrazone Schiff bases” J. Organomet. Chem. 690. 1669–1676.

[18] Ma. C., Jiang, Q. and Zhang, R. (2004) “Synthesis, characterization and crystal structures of new organotin complexes with 2-mercapto-6-nitrobenzothiazole” Polyhedron 23. 779-786.

29


STUDY ON BIMETALLIC NI/CO CATALYST DOPED WITH PRASEODYMIUM USING VARIOUS SUPPORT FOR CO / H METHANATION TOWARDS

In this study, a group of Ni bimetallic catalyst added with other elements to form Ni/Co/Pr catalyst with the atomic o several selected support, namely cordierite (2MgO-2Al2O3-5SiO2), alumina ].x H2O), to determine the best support for the CO2 elimination catalyst. During

e investphase for

ility of the catalyst against sintering.

ord lt, support

4 sekata dan kemudiannya berubah menjadi Ni3+ dan CoO selepas ujian

inan seterusnya mendapati tiada karbon terbentuk diatas permukaan mangkin yang enunjukkan ketahanan mangkin.

a k

.0 Introduction

have received much attention as often these systems exhibit ility making them superior to the monometallic catalysts for a

is largely employed in process in the petroleum industry rod ing, etc.), fine chemical synthesis (hydrogenation and

isomeriz

alt catalyst with short chains.

2 2PURIFICATION OF NATURAL GAS

Faridah Mohd Marsin, Nor Aziah Buang*, Wan Azelee Wan Abu Bakar, Mohd Hasmizam Razali

Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia,

81310, Skudai, Johor, Malaysia.

Abtract:ratio of 60:35:5 has been washcoated ontAl(

th2O3), and molecular sieve (Na12[(AlO2)12

igations of its catalytic performance, amount of nickel loading, the reaction temperature, the durability, and the med during reaction were also examined. Based on the results obtained, cordierite was found to be the best support

for eliminating CO2 by converting to CH4 at approximate 100% at 350°C during catalytic testing. Further characterization using X-Ray Diffraction and Scanning Electron Microscopy showed that the catalyst on cordierite support formed Ni2+ and spinel compound Co3O4 was evenly distributed onto the support, which later will form Ni3+ and CoO after the first catalytic testing that enhance the catalytic performance of the catalyst. The latter testing also showed no carbon decomposition of the catalyst, which proves the durab

Keyw s: Ni based catalyst, CO2 elimination, coba Abstrak: Di dalam penyelidikan ini, mangkin campuran nikel telah ditambah dengan beberapa elemen lain untuk menyediakan mangkin Ni/Co/Pr dengan nisbah 60:35:5. Mangkin telah di isitepu ke atas beberapa penyokong terpilih iaitu, cordierite (2MgO-2Al2O3-5SiO2), alumina (Al2O3), dan molecular sieve (Na12[(AlO2)12].x H2O). Mangkin yang disediakan telah diuji untuk mendapatkan jenis penyokong terbaik bagi mangkin penyingkiran CO2. kajian ini memfokuskan kepada keupayaan mangkin, suhu tindakbalas, fasa yang terbentuk, saiz zarah, dan ketahanan mangkin. Hasil diperolehi mendapati kordierite merupakan penyokong yang terbaik bagi penyingkiran CO2. Ini kerana ia dapat menyingkirkan hampir 100% CO2 daripada sistem dengan menukarkan CO2 kepada CH4 pada suhu 350°C. Seterusnya, kajian pencirian menggunakan embelauan sinar X (XRD) dan Mikroskopi Pengimbas Elektron (SEM) mendapati bahawa Ni2+ dan sebatian spinel Co3Op

terbentuk di atas permukaan mangkin secara pemangkinan dijalankan.ujian pemangkm Kat unci: mangkin berasaskan nikel, penyingkiran CO2, cobalt, penyokong

1

Supported bimetallic catalystsigher activity, selectivity and/or stabh

given reaction [1,2]. This type of catalysts(hyd esulfurization, hydrocarbon reform

ation reactions), partial oxidations or automobile emission control catalysts. Nickel oxide exhibited high activity and selectivity of methane due to the ability of NiO to

undergo reduction process owing to the presence of defect sites of the surface [3] Despite of the fast catalyst deactivation and carbon deposition, NiO catalyst was still favored for its high thermal stability [4], and its low price [5]. The addition of selected metal into nickel oxide base catalyst was found to enhance the capability of the catalyst. The usage of catalyst will depend on the dopant used in order to form a durable, sulfur tolerant, high catalytic activity catalyst.

Cobalt was mainly used for Fisher-Troposh Synthesis (FTS) and was chosen due to its reducibility of CO. Jacobs et al. [6] found that addition of Ru and Pt exhibited a similar catalytic effect on decreasing both the reduction temperatures of cobalt oxides. The hydrogenation of CO and CO2 were found to catalyze by the larger cobalt clusters formed by three incipient wetness impregnations [7]. Other research by Guczi et al. [8] found that Co–Pd samples are fully reducible and form bimetallic particles that can be reversibly oxidized/reduced. CO hydrogenation takes place n the range of 200–300oC producing mainly alkenes on pure cobi

30


Synergism on the addition of small amount of palladium to cobalt is observed and the rate of the CO ydrogenation significantly increases.

In this research, bimetallic Ni was added with cobalt and praseodymium, in the optimized atomic ratio of 60:35:5, on different supports; namely cordierite, alumina, and molecular sieve, and it was used to eliminate CO2 with the presence of H2 with the hopes for CO2 hydrogenation to occur. The reducibility and characteristics of the Ni based catalysts were tested by means of FTIR for catalytic activity of CO2 eliminated and methane produced, X-Ray Diffraction for phase or structural changes, Scanning Electron Microscopy for the determination of particle size and distribution. 2.0 Experimental 2.1 Catalyst preparation

Ni/Co/Pr solution in atomic ratio of 60:35:5 was prepared via optimized sol gel method. This method includes the addition of its specific metal salts with its base metal, Ni(NO3)2.6H2O, and second dopant, Pr(NO3)3.6H2O. Using incipient wetness method, the selected support was then impregnated with the catalyst solution. It was then aged at 75°C for 48 hours before it was calcined at 400°C for 17 hours.

The prepared samples were then tested for its capability to eliminate CO2 by methanation ic

ressure. The reaction gas mixture of CO2 and H2 was passed continuously through the catalyst that was fill

ing a

atalytic activity measurements

Figure 1 showed that cordierite supported catalyst showed superiority than alumina and olecular sieve supported catalyst. It was figured by the high percentage of CO2 elimination at 350°C 0%). Whilst the others, Al2O3 manage to reach 90% at 500°C, and molecular sieve was at 78%, also

t 500°C. From the bar chart it is clearly seen that cordierite supported catalyst manage to yield the ighest percentage of CH4. The CH4 was detected as low as 300°C and increased steadily throughout e testing. Meanwhile CH4 in Al2O3 supported catalyst was detected at a high temperature of 450°C,

ence molecular sieve did not detect any CH4. As we varied the amount of Ni and Co in the catalyst, we found out that only a certain amount

f Ni and Co must be present in order to have an efficient methanation catalyst. This can be seen in igure 2, whereby to have a high catalytic activity the optimized ratio is Ni/Co/Pr with the ratio of 0:35:5, as it showed superiority in both CO2 elimination and CH4 conversion. With the addition of o in the catalyst, the amount of CO2 eliminated and CH4 detected constantly decreased. We can onclude that the optimized ratio for the supported catalyst is 60:35:5.

h

2.2 Catalytic activity measurement

reaction. This was done using a flow bed reactor of 10 mm inner diameter under atmospherp

ed inside the sample tube that flows through the FTIR whereby the CO2 peaks from the composition of the gas will be detected. The temperature of the sample ranged from 25-500°C. The tabulated data gave percentages of CO2 eliminated and CH4 converted within the temperature range. 2.3 Characterization 1. X-ray Diffraction Analysis : The catalyst samples were characterized by using a Philips D5000

X-Ray Diffractometer (Cu-Kα radiation) with a degree ranging from 10-80°, 2. Scanning Electron Microscopy Analysis: Best performance catalysts were scanned us

Philip XL 40 SEM 3.0 Results and disscussion 3.1 C

m(9ahthh oF6Cc

31


50

60

n (%

) 70

80

)

0

10

20

30

40

25 50 100 150 200 250 300 350 400 450 500

temperature

CH

4 co

nver

si

0

10

20

30

40

50

CO2

elim

inat

70

80

o 60

90

100

ion

(%

kd ab mskd ab ms

Figure 1: catalytic activity of supported catalyst

0

10

20

30

40

50

60

70

80

CH4

con

vers

ion

(%)

50

60

70

80

90

100

2 el

imin

atio

n (%

)25 50 100 150 200 250 300 350 400 450 500

temperature

0

10

20

30

40

CO

nicopr 60:35:5 nicopr 50:45:5 nicopr 47.5:47.5:5 nicopr 45:50:5nicopr 60:35:5 nicopr 50:45:5 nicopr 47.5:47.5:5 nicopr 45:50:5

Figure 2: catalytic activity of cordierite supported Ni/Co/Pr with various ratios (a) 60:35:5, (b) 50:45:5, (c) 47.5: 47.5: 5, and (d) 45:50:5.

0102030405060708090

100

1 2 3 4 5experiments (TOF)

perc

enta

ge C

H4

conv

ersi

on/ C

O2

elim

inat

ion

CH4 CO2 Figure 3: percentage of CO2 elimination and CH4 converted at 350°C using the same catalyst during several experiments

The best-supported catalyst was then put into test to perceive the life span of the catalyst. Figure 3 showed percentage of CO2 elimination and the CH4 yielded at 350°C using the same catalyst during several experiments. It was found out that after the first experiment (70% CO2; 40% CH4), the catalytic activity of the catalyst enhances to 90% CO2 and 80% CH4. However as the experiments continue, the catalytic activity of the catalyst started to decrease until at fifth experiment only 30% of

32


33

CO2 eliminated, while 20% CH4 yielded. It was predicted that the presence of Co3O4 spinel compound enhances the catalytic activity, and as the spinel compound decreases, so does the catalytic activity. It was assumed that the spinel compound bonded with the support to form ternary compound MgCoO. Further study on the characterization of the catalyst was done in order to proof the assumption.

3.2 Characterization 3.2.1 X-Ray Diffraction analysis

sure of CO2 and H2.

(a) as after fifth exposure of CO2 and H2. As

we ca

.2

differmi75

homosurfac ems to form crystallites and agglomerated on the surface of the support. Thus pores

rmed in between the sintering. The interaction of the catalyst and cordierite was presumed to be strong, as it formed ternary compound in the former XRD diffractogram.

Figure 4: diffractogram of cordierite supported CO

Ni/Co/Pr with the ratio of 60:35:5 (a) as prepared, (b) after first exposure of 2 and H2, (c) after fifth expo

Figure 4 showed the diffractogram of cordierite supported Ni/Co/Pr with the ratio of 60:35:5

prepared, (b) after first exposure of CO and H2prepared, the catalyst exhibits NiO, Co3O4 spine

2, (c)l compound, and also ternary compound, which are

MgNiO and MgCoO. As it was exposed to CO2 and H2, the spinel compound started to decrease and n see the rising of MgCoO peak, which means the addition to the ternary compound. At the fifth

exposure, the Co3O4 spinel has gone, while the MgCoO increased. This corresponds with the catalytic activity of the catalyst, which has decreased throughout exposure.

3.2 Scanning Electron Microscopy

As we compare SEM micrograph of the three different supported catalysts, we can see a big ence in its structure. Molecular sieve has the smallest particle size of 1.011 µm, followed by

µalu na 1.375 m, and the biggest particle size is by the best-supported catalyst, cordierite, with 4.3 µm. Though at this stage the particle size do not influence its catalytic activity. Though alumina has the smallest particle size, it has the lowest catalytic activity. Both Al2O3 and molecular sieve is

genous, evenly distributed and covered with pores. However for cordierite, which has low e area, se

fo

42-1467 (*) - Cobalt Oxide - Co3O4 02-1073 (N) - Magnesium Cobalt Oxide 24-0712 (*) - Magnesium Nickel Oxide -

84-1221 (C) - Cordierite - Mg2Al4Si5O18

2-Theta - Scale

6 1 2 3 4 5 6 7

(c)

(b)

(a)


Figure 5: SEM alumina bead supported catalyst after calcined hours (a) 1000 x and (b) 5000 x magnification

at 400°C for 17

Figure 6: SEM molecular sieve supported catalyst after calcined at 400°C for 17 hours (a) 1000 x and (b) 5000 x magnification

Figure 7: SEM cordierite supported catalyst after calcined at 400°C for 17 hours (a) 1000 x and (b) 5000 x magnification 4.0 Conclusion and suggestions From the study it was clear that cordierite supported catalyst showed superiority from the other supports. Results showed that only optimized ratio of the catalyst on the support will show the highest catalytic activity. The optimized ratio depicted was Ni/Co/Pr with the ratio of 60:35:5. However the turnover frequency showed that after the second testing, the catalytic ability declined.

his was due to the transformation of Co3O4 spinel compound to ternary compound MgCoO, which support. The SEM micrographs showed

gglomeration and crystallization on the cordierite supported catalyst, compared to alumina and olecular sieve, which have small particle size and evenly distributed particles. Further study should

der to maintain the presence of Co3O4 spinel compound in the catalyst for a long period of time to add the life span of the catalyst.

Tforms strong bonds between the catalyst and theambe done in or

5.0 Acknowledgements The writers would like to thank the Ministry Of Science Technology Education for a research grant. The financial support of MOSTE under project (vot: 74178) is recognized. 6.0 References 1. Guczi, L., and Sarkany, A., in: J.J. Spivey, S.K. Agarwall (Eds.), “Catalysis” Specialist Periodical Report,

vol. 11, Royal Society of Chemistry, London, 1994, p. 318. 2. Ponec, V., Appl. Catal. A: Gen. 222 (2001) 31.

34


3. Jose, A., R., Jonathan, C., H., Anatoly, I., F., Jae, Y., K. and Manuel, P. (2001). Experimental and Theoretical Studies on the Reaction of H2 with NiO. Role of O Vacan cies and Mechanism for Oixde Reduction. J. Am. Chem.Soc. 124, 346-354

4. Wang, L., Murata, K., and Inaba, M. (2004). Control of the Product Ratio of CO2/ (CO+CO2) and Inhibition of Catalyst Deactivation for Steam Reforming of Gasoline to Produce Hydrogen. Applied Catalysis B: Environmental. 48: 243-248

5. Hou, Z., Yokota,O., Tanaka, T., and Yashima, T. (2004). Surface Properties of a Coke-free Sn Doped Nickel Catalyst for the CO2 Reforming of Methane. Applied Surface Science. 233: 58-68.

6. Jacobs, G., Das, T.K., Zhang, Y., Li, J., Racoillet, G., and Davis, B.H. (2002). Fisher-Troposh synthesis: support, loading, and promoter effects on the reducibility of cobalt catalyst. Applied Catalysis A: General

-281. . Zhang, Y., Jacobs, G., Sparks, D.E., Dry, M.E., and Davis, B.H. (2002). CO and CO2 hydrogenation

233: 2637

study on supported cobalt Fisher-Troposh synthesis catalysts. Catalysis Today 71: 411-418 8. Guczi, L., Schay, Z., Stefler, G., and Mizukami, F. (1999). Bimetallic catalysis: CO hydrogenation over

palladium–cobalt catalysts prepared by sol gel method. Journal of Molecular Catalysis A: Chemical. 141: 177–185.

35


KAJIAN KRISTALOGRAFI SINAR-X KOMPLEKS [µ-1(2-PIRIDIL-κN)ETANON 4-FENILTIOUREASEMIKARBAZONATO-κ2N1,S]BIS[IODOMERKURI(II)] DAN

BIS(N-4-METOKSIBENZOIL)-N’-O-TOLILTIOUREA-κS)DIIODOMERKURI(II)

Mohd Sukeri Mohd Yusof1* & Bohari M. Yamin2.

1Jabatan Sains Kimia, Fakulti Sains dan Teknologi Malaysia, Kolej Universiti Sains dan Teknologi Malaysia, Mengabang Telipot, 21030 K. Terengganu. 2Pusat Pengajian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor.

Abstrak KBis(

ompleks [µ-1(2-piridil-κN)etanon 4-feniltioureasemikarbazonato-κ2N1,S]bis[iodomerkuri(II)], dan N-4-metoksibenzoil)-N’-o-toliltiourea-κS)diiodomerkuri(II), mempunyai formula molekul

masing-masing Hg2(L)2I2 dan Hg(L)2I2. Kedua-dua kompleks, mempunyai sistem hablur monoklinik dengan kumpulan ruang masing-masing adalah C2/c, a=18.466(3)Å, b=16.745(2)Å, c=13.9140(19)Å, β=129.174(2)º dan P21/c, a=10.848(3)Å, b=24.474(7)Å, c=14.038(4)Å, β=92.206(4)º. Dalam kompleks merkuri-bes Schiff, atom Hg mempunyai geometri segi empat pyramid di mana ligan terikat secara tridentat melalui atom NNS. Atom Sulfur kedua-dua ligan membentuk jejambat menghubungkan dua atom Hg menjadikan bentuk keseluruhan molekul seperti kotak. Sebaliknya, dalam kompleks merkuri-tiourea atom merkuri berkoordinat dengan ligan melalui atom S kumpulan tion secara monodentat dan bersifat dimerik ,menjadikan geometri Hg tetrahedron terherot.

Abstract Both [µ-1(2-pyridyl-κN)ethanone 4-phenylthioureasemicarbazonato-κ2N1,S]bis[iodomercury(II)], and Bis(N-4-methoxybenzoyl)-N’-o-tolylthiourea-κS)diiodomercury(II), comp have the molecular

rmula of Hg2(L)2I2 and Hg(L)2I2 where L is the ligand, respectively also crystallized in

/c, a=10.848(3)Å, b=24.474(7)Å, c=14.038(4)Å, =92.206(4)º, respectively. In Schiff base ligands are coordinated to the mercury atom via their (NNS) donor

n the ercury-thiourea complex is coordinated to the ligands via the thiono sulfur atoms in a monodentate

manner and form a d

Kata kun kuri kompleks, tiourea, benzoiltiourea Pengen

Masalah aran oleh log utama dalam sistem akueus seperti air buangan yang disalurk ngai masih meru aman hingga ilang-kilang y ggung

wab su ya me arang kaedah atau teknik yang boleh m

ebut adalah melalui engkompleksan dan seterusnya terpisah daripada larutan. Kajian awal kami mendapati terbitan

tiourea mampu membentuk kompleks dengan beberapa logam kini mendapat tumpuan. Baru-baru ini

berat daripada buangan akueus

(Rether & Schunster, 2003). Beberapa sebatian terbitan tiourea telah menunjukkan kemampuan yang

lexes . Theyfo

monoclinic system, but having space group is C2/c, a=18.466(3)Å, b=16.745(2)Å, c=13.9140(19)Å, β=129.174(2)º and P21 β

e first complex, the thatoms in a tridentate manner. The sulfur atoms act as a bridge connecting the Hg atoms, forming a rectangular base that almost perpendicular to the ligand planes, resulting in an open box-like structure. The geometry of the mercury atom is close to a square pyramid. However, the mercury atom im

istorted tetrahedral geometry.

ci: Mer

alan pencem a rm berat tean ke sudah pasti sepatutn

pakan ancnerima baik seb

ke hari ini. K ang bertanemisahkan ja

logam berat dan toksik di loji masing-masing daripada menyalurkan ke dalam sungai. Untuk itu penyelidikan mencari bahan dan teknik yang murah, mudah dan efisien untuk memisahkan logam-ogam toksik terus berkembang. Satu daripada kaedah pemisahan logam tersl

p

benzoiltiourea yang diubahsuai di atas silica mesoporos MCM-48 didapati menjerap raksa daripada larutan akueus (Olkhovyk et al. 2004). N-benzoiltiourea yang diubahsuai bersama polimer PAMAMdapat memisah secara terpilih dan mengumpul semula ion logam

36


tinggi untuk membentuk kompleks dengan logam berat terutamanya raksa dan kadmium (Yamin & Yusof, 2004). Kajian struktur tentang kompleks merkuri-tiourea telah banyak dilaporkan, tetapi kebanyakannya adalah kompleks merkuri-siklotiourea seperti Hg(C8H16N4S2)Cl2, Hg(C8H16N4S2)Br2, Hg(C8H16N4S2)I2, Hg(C8H16N4S2)(SCN)2 dan Hg(C8H16N4S2)(CN)2 (Popovic et al., 2000). Hanya terdapat beberapa laporan tentang kompleks merkuri-tiourea (gelang terbuka) seperti Bis(o-

lorofenilbenzoiltiourea-κS)-diiodomerkuri(II) (Yusof et.al.,2004) dan bisµ-kloro-kloro[(N-dietilaminotiokarbonil)benzimido-O-metil ester-S]merkuri(II) (Leβmann et al., 2000). Kertas ini membincangkan struktur kompleks merkuri-bes Schiff dan merkuri-tiourea. Eksperimen Tindak balas pengkompleksan dilakukan dengan merefluks ligan N-fenil-2-(1-piridin-2-iletil)hidrazinakarbotioamida dan N-4-metoksibenzoil)-N’-o-toliltiourea masing-masing dengan merkuri iodida (HgI2) dalam pelarut etanol selama 3 jam. Hasil refluks dituras dan dibiarkan menyejat pada suhu bilik dan menghasilkan hablur yang kekuningan. Hablur yang diperolehi dianalisis untuk menentukan struktur hablur dengan menggunakan alat pembelauan sinar-X hablur tunggal. Keputusan & Perbincangan Kompleks Bis[µ-1(2-piridil-κN)etanone 4-feniltioureasemikarbazonato-κ2N1,S]bis[iodomerkuri(II)], Hg2(C14H13N4S)2I2], (I) dan Bis(N-4-metoksibenzoil)-N’-o-tolyltiourea-κS)diiodomerkuri(II),

4(7)Å, c=14.038(4)Å dan β=92.206(4)º. Data hablur dan parameter enghalusan kedua-du

dual 1: Dat lusan data hab pleks (I) dan

erkara Kompleks Komp

k

Hg[C16H16N2O2S]2I2, (II), masing-masing mempunyai sistem hablur monoklinik dengan kumpulan ruang C2/c, sel unit a=18.466(3)Å, b=16.745(2)Å, c=13.9140(19)Å dan β=129.174(2)º dan P21/c, =10.848(3)Å, b=24.47a

p a kompleks ditunjukkan dalam Jadual 1.

Ja a hablur dan pengha lur kom (II)

P I leks II FormulaBerat m

(C14H13N4S)2I23.67

Hg[C16H16N2O1055.13

empirik olekul

Hg2119

2S]2I2

Sistem hablur, kumpulan ruang noklinik, C2/c Monoklinik, PDimensi sel unit 18.466(3)Å Å

awasan theta untuk pungutan data 1.8 hingga 27.6º 1.66 hingga 27.50

40517/8483[R(int) = 0.053]

lengkap lengkap ata / kekailai ketepdek I>2sigma(I)] R1 = 0.0423, 4 R1 = 0.0413, wR2 = 0.0911

Indeks R (semua data) R1 = 0.050 9 .0560, wR2 = 0.0975 Pe k dan luban 0.219 dan - e. Å-3 an -0.842 e

Mo 21/c a =b = 16.745(2)Å c = 13.9140(19)Å β = 129.174(2)º

b=24.474(7)Å, c=14.038(4)Å β=92.206(4)º

Isipadu 3335.3(8) Å

a=10.848(3) ,

3 3724.2(18) Z, ketumpatan 4, 2.377 Mg/m3 4, 1.882 Mg/m3

Saiz hablur 0.38 x 0.18 x 0.13 mm 0.47 x 0.39 x 0.07 mm KSet data -24<=h<=24, -21<=k<=21,

-18<=l<=18 -14<=h<=14, -31<=k<=21, -18<=l<=18

ungutan pantulan/ unik 3875 / 3277 [R(int) = 0.033] PKesempurnaan kpd. theta=27.6/27.5 º 99.5% 99.1% Pembetulan serapan Multi-scan Multi-scan Mak. dan min. transmisi 0.9288 dan 0.8624 0.6811 dan 0.1667 Kaedah pemprosesan Kuasa dua terkecil matriks- Kuasa dua terkecil matriks-

D ngan / parameter 3175 / 0 / 193 8483/0/406 atan struktur (GooF) 1.081 1.084 N

In s akhir R [ wR2 = 0.1126, wR2 = 0.118 R1 = 0

rbezaan p ncau g 0.237 1.343 d . Å-3

37


Ba (I), ligan nil-2-(1-piridin-2- hidrazinakarb a merupa ligan tridentat iaitu berkoordinat dengan atom Hg1 melalu N3, N4 dan jah 1). Ini a satu c kuri berko t lebih daripada 2 jarang berlaku. Molekul kompl dalah dimerik dengan dua atom Hg dihubungkan dengan ikatan jejam ada dua at dan m k seperti ko ang terbuka. Panja tan Hg-S [2. dalam k eks I adalah pendek sedikit berbanding dalam kompleks bis(o nilbenzoiltiourea-κS)-d (Yusof et 2003). Panjang I C7-S1, 1.76 adalah lebi jang

o-klorofenilbenzoiltiourea-κS)-diiodomerkuri(II) [1.690(6) Å]. anjang ikatan dan sudut yang lain adalah dalam jarak yang normal (Allen et al., 1987; Orpen et al., 989) dan juga bersamaan dengan kompleks bes-Schiff yang lain seperti [Mn(C14H13N4S2)2] (Usman

dut dihedral bagi kedua-dua ligan ialah 9.07(11)º.

gi kompleks N-fe iletil) otioamid kan i atom S1i ( Ra dalah

ontoh logam mer ordina yang eks a dua bat darip om S

olekul berbentu tak y ng ika 6840(16)Å] ompl-klorofe

iiodomerkuri(II) al., katan 8(4) Å h pandibandingkan dengan kompleks bis(P1et al., 2002). Su

Rajah 1: Gambarajah ORTEP molekul kompleks (I) pada kebarangkalian 30% tanpa atom H untuk gambaran lebih jelas. Geometri bagi kedua-dua atom Hg adalah antara trigonal bipiramid dan piramid planar tetapi mendekat ii kepada piramid planar. Atom N3, N4, S1 dan I1 adalah sesatah dengan pesongan maksimum sebanyak 1.491(1) Å. Sudut pusat atom Hg adalah antara 67.63(12) dan 107.74(2)º.

Jadual 2: Panjang ikatan dan sudut ikatan dalam kompleks (I)

Ikatan Panjang Ikatan, Å Ikatan Sudut Ikatan, º Hg1-N4 2.387(4) N4-Hg1-N3 67.63(2) Hg1-N3 2.398(3) N4-Hg1-S1i 140.71(9) Hg1-S1i 2.6173(11) N3-Hg1-S1i 73.32(9) Hg1-S1 2.6490(12) N4-Hg1-S1 95.73(9)

i 1.290(5) S1i-Hg1-S1 93.48(3) Hg1-I1 2.6635(4) N3-Hg1-S1 97.71(8) N2-C7

Molekul kompleks distabilkan oleh ikatan hidrogen inter-molekul, N1-H1A…I1ii, [simetri kod; (ii) 3/2-x,1/2-y,1-z] membentuk rantaian zig-zag yang selari pada paksi-a (Rajah 2).

38


Rajah 2: Gambarajah padatan molekul dalam sistem hablur, dilihat ke dalam paksi c. Garisan putus-putus menunjukkan ikatan hydrogen inter-molekul N-H…I.

Kompleks (II) adalah dimerik (Rajah 3) dengan dua molekul ligan berkoordinat dengan atom pusat, Hg1 melalui atom sulfur, S. Atom pusat Hg1 mempunyai geometri tetrahedral terherot dengan sudut antara 96.18(4)º dan 133.75(2)º. Panjang ikatan dan sudut ikatan adalah normal (Allen et al., 1989;

rpen et al., 1980) dan berpadanan dengan kompleks bis(o-klorofenilbenzoiltiourea-κS)-Odiiodomerkuri(II) (Jadual 4).

Rajah 3: Gambarajah ORTEP molekul kompleks dengan kebarangkalian 50% tanpa atom H untuk gambaran lebih jelas.

Jadual 3: Panjang ikatan dan sudut ikatan dalam kompleks

Ikatan Panjang Ikatan, Å Ikatan Sudut Ikatan, º

Hg1-I1 2.6558(6) I1-Hg1-I2 133.75(2) Hg1-I2 2.6700(6) I1-Hg1-S2 104.47(3) Hg1-S1 2.6762(13) I2-Hg1-S2 110.47(3)

92(14) I1-Hg1-S1 108.21(3) Hg1-S2 2.71S1-C8 1.698(5) I2-Hg1-S1 97.31(3)

S2-C24 1.709(4) S2-Hg1-S1 96.18(4)

39


Panjang ikatan Hg1-I1 dan Hg1-I2 [2.6558(6)Å dan 2.6700(6)Å], didapati lebih pendek jika dibandingkan dalam kompleks Hg(C8H16N4S2)I2 [2.7123(5)Å] (Popovic et al., 2000) tetapi bersesuaian dengan panjang ikatan seperti dalam kompleks bis(o-klorofenilbenzoiltiourea-κS)-diidomerkuri(II) [2.6582(6)Å] (Yusof et al., 2004). Ikatan Hg1-S1 [2.7192(14)Å adalah lebih panjang berbanding dalam kompleks bis(o-klorofenilbenzoiltiourea-κS)-diidomerkuri(II) [2.6840(16)Å].

ajah 4: Gambarajah padatan molekul kompleks yang dilihat pada permukaan ab. Garisan putus-Rputus menunjukkan ikatan hidrogen inter-molekul N-H…O dan C-H…I.

drogen intra-molekul, N-H…S, N-H…O dan C-H…N [Jadual 3] yang Terdapat enam ikatan hymemberikan 4 gelang pseudo-enam ahli (Rajah 3). Dalam sistem hablur, molekul terikat melalui ikatan hidrogen inter-molekul N-H…O dan C-H…I (Jadual 4) membentuk dimer yang dilihat melalui permukaan ab (Rajah 4).

Jadual 4: Senarai ikatan hidrogen intra- dan intermolekul dalam kompleks (Å,°).

D-H…A D-H H…A D…A D-H…A N1-H1A S2 0.86 2.76 3.5135 147 …

N2-H2A…O1 0.86 1.98 2.6558 134

2.32 3.0124 137 C16-H16B I2 0.96 2.97 3.9245 173

N3-H3A…S1 0.86 2.76 3.5762 159 N4-H4A…O3 0.86 1.98 2.6419 133

C16-H16A…N2 0.96 2.38 2.8546 110 C32-H32A…N4 0.96 2.38 2.8660 111 N2-H2A…O3i 0.86 2.36 3.0661 139 N4-H4A…O1ii 0.86

… i

Sim Penghargaan P kan da Ke an Mal , Univ i Keba an MaUniversiti Sains dan Teknologi Mala diatas k dahan telah diberikan

etri kod; (i) 1+x,y,z; (ii) -1+x,y,z

enghargaan diberi kepa raja aysia ersit ngsa laysia dan Kolej ysia emu yang

40


Rujukan Allen, F.H., Kennard, O., Watson, D.G., Orpen, A.G. & Taylor, R. 1987. J. Chem. Soc. Perkin Trans. 2:S1-19. Leßmann, F., Beyer, L., & Sieler, J. 2000. Synthesis and X-ray structure of the first chloro-bridged thiourea mercury(II) complex [C6H5C(OCH3)NC(S)N(C2H5)2HgCl2]2. Inorganic Chemistry Communications. Vol 3: Issue 2:62-64. Olkhovyk, O., Antochshuk, V., & Jaroniec, M. 2004. Benzoylthiourea-modified MCM-48 mesoporous silica for mercury(II) adsorption from aqueous solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspect. Vol. 236, 1-3:69-72. Orpen, A.G., Brammer, L., Allen, F.H., Kennard, O., Watson, D.G., & Taylor, R. 1989. J. Chem. Soc. Dalton Trans. S1-83. Popovic, Z., Pavlovic, G., Matkovic, D., Soldin, Z., Rajic, M., Vikic, D., & Kovacek, D. 2000. Mercury(II) complexes of heterocyclic thiones.: Part 1. Preparation of 1:2 complexes of mercury(II) halides and pseudohalides with 3,4,5,6-tetrahydropyrimidine-2-thione. X-ray, thermal analysis and NMR studies. Inorganica Chimica Acta, Vol. 306: Issue 2:142-152. Rether, A. & Schuster, M. 2003. Selective separation and recovery of heavy metal ions using water-oluble N-benzoylthiourea modified PAMAM polymers. Reactive and Functional Polymers, Vol. 57, :13-21

Y dimethylsulfoxidedisolvate. Acta Cryst.

amin, B. M. & Yusof, M. S. M. 2003. N-[N-(Furan-2-carbonyl)hydrazine thiocarbonyl]benzamide. cta Cryst. E59:o124-o126.

Kassim, M. B. 2004. Bis(o-chlorophenylbenzoyl thiourea-

s1 .

amin, B. M. & Yusof, M. S. M. 2003. N,N'-Bis(benzamidothiocarbonyl)hydrazineE59: o358-o359.

YAYamin, B. M. & Yusof, M. S. M. 2003. N'-Benzoyl-N-p-bromophenylthiourea. Acta Cryst.. E59: o340-o341. Yamin, B. M. & Yusof, M. S. M. 2003. N-Benzoyl-N'-phenylthiourea. Acta Cryst. E59: o151-o152. Yamin, B. M., Kassim, M. B., Yusof, M. S. M. & Shah, N. M. 2004. N-Benzoyl-N'-ethylthiourea. Acta Cryst. E60: o556-o557. Yusof, M. S. M. & Yamin, B. M. 2004. N-Benzoyl-N’-(2-chlorophenyl)thiourea. Acta Cryst. E60: o1403-o1404. Yusof, M. S. M. & Yamin, B. M. 2003. 3-(3-Benzoylthioureido)propionic acid. Acta Cryst. E59: o828-o829. Yusof, M. S. M., Yamin, B. M. & Shamsuddin M. 2003. N-(N-Benzoylhydrazino carbothioyl)benzamide. Acta Cryst. E59: o810-o811. Yusof, M. S. M., Yamin, B. M. &S)diiodomercury(II). Acta Cryst. E60: m98-m99.

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S

N

bstract Subcritical water extraction (SWE) is a technique based on the use of water as an extractant, at temperatures between 100 and 374 ºC and at a pressure high enough to maintain the liquid state. As the temperature of liquid water is raised under pressure, the polarity decreases and it can be used as an extraction solvent for a wide range of compounds. The application of SWE in the extraction of essential oil from coriander (Coriandrum sativum L.) seeds was studied. Ground coriander seeds (3-4 g) were subjected to SWE with water for an extraction time of 15 min under several extraction conditions (pressures of 870 and 1000 psi and temperatures of 65, 100 and 150 ºC). The SWE method was compared with hydrodistillation performed by treating 10 g of ground coriander seeds with 100 mL of water for 3 hours. Compounds were removed from the aqueous extract with hexane and determined by gas chromatography mass spectrometry (GC-MSD). It was found that the efficiency (g oil/g of coriander) of SWE was higher than that provided by hydrodistillation with reduced extraction time. The major compounds found were linalool, isoborneol, citronellyl butyrate and geraniol. SWE method has the possibility of manipulating the composition of the oil by varying the temperature and adjusting the pressure. Keywords: Subcritical water extraction, Coriander, Coriandrum Sativum L. Introduction Before the essential oils of plants can be analyzed, they have to be extracted and concentrated, and a number of different methods can be used for that purpose such as hydrodistillation, steam distillation and solvent extraction. Air dried leaves are usually subjected to hydrodistillation or steam distillation for about 3-8 hours and the essential oils are dried over anhydrous sodium sulfate. In solvent extraction (cold or hot), extraction of the air-dried plant material is carried out using an appropriate solvent depending on the nature of the essential oils. Several drawbacks such as low yield, losses of volatile compounds, long extraction times, degradation of unsaturated compounds and toxic solvent residue in the extract may be encountered with the current extraction methods [1]. These shortcomings have led to the emergence of new techniques in the extraction of essential oils such as supercritical CO2 extraction (SFE) [1,2] and solvent free microwave extraction [3]. In recent years extraction with superheated water or subcritical water extraction (SWE) has been used widely for the extraction of polar and non polar analytes from environmental samples. SWE has also been applied in the extraction of essential oil from plants [4,5]. In this work subcritical water extraction of coriander seeds was compared to hydrodistillation in terms of extraction yields and essential oil composition. The influence of extraction conditions (temperature and pressure) on the composition of essential oil was analyzed. Experimental Sample preparation Coriander seeds were purchased from local stores. The seeds were crushed before analysis. Subcritical water extraction (SWE) SWE was performed using an accelerated solvent extraction system, ASE 200, equipped with a solvent controller unit from Dionex Corporation. Extractions were performed using water with a static

UBCRITICAL WATER EXTRACTION OF ESSENTIAL OIL FROM CORIANDER (Coriandrum sativum L.) SEEDS

orashikin Saim*, Rozita Osman, Wan Azriza Hirmi Md Yasin, Rossuriati Dol Hamid

Fakulti Sains Gunaan, Universiti Teknologi MARA 40450 Shah Alam, Selangor

e-mail: [email protected] A

42


e SWE 2: 870 ps 0 psi, 100 ˚C, SWE 6: 1000 psi, 150 ˚C) All extractions were performed in 22 mL extraction cells, containing 3 g of sample. The extraction procedure was as follows: (i) sample is loaded into cell; (ii) cell is filled with solvent up to a specific on is performed for 15 min (v) the cell is rinsed (with 60% cell volume using extraction solvent); and (vi) solvent is purged from the cell with N ng hexane and HCl was the yield was dete mined in until analyzed by GC–MSD.

gh purity)

.8%) were found to be higher than that obtained by hydrodistillation (0.06-0.1%). Lower yields (~ pressure conditions. The

ecreased in yield at higher temperature was also reported by other researchers [4,6]. It was observed re no significant difference in the amounts of extracted oil obtained under different

ressures but same temperatures. The reduced extraction time (3 hours for hydrodistillation against

ods. Major compounds identified were linalool, isoborneol, citronel

xtraction time of 15 min at different extraction temperatures and pressures (SWE 1: 870 psi, 65 ˚C,i, 100 ˚C, SWE 3: 870 psi, 150 ˚C, SWE 4: 1000 psi, 65 ˚C, SWE 5: 100

pressure and temperature (iii) a static extracti

2 gas. Following SWE, liquid-liquid extraction step was performed usiadded to facilitate the breaking of emulsion. The obtained oil was separated and

r terms of dry basis yield. The oil was stored in a freezer at -4 °C

Hydrodistillation Ten grams of crushed coriander seeds were subjected to hydrodistillation using 100 mL of distilled water for 3 h after the mixture had reached boiling point (100 °C). Liquid-liquid extraction step was performed using hexane. The obtained oil was separated, and the yield was determined. It was stored in a freezer at -4 °C until analyzed by GC–MSD. Gas chromatography-mass spectrometry (GC-MS) analyses GC-MS analysis was performed on an Agilent gas chromatography model 6890N coupled to a mass selective detector 5973 inert. Compounds were separated on a cross-linked fused silica capillary column HP5-MS (30m x 250µm x 0.25µm). The head pressure of the carrier gas helium (hiwas 50 kPa. The temperature programmed was set at an initial 60 °C, followed by an increase by 10 °C min-1 to 200 °C and held for 15 minutes. The MS detector was operated in the full scan mode with 70 eV electrons ionization, by scanning a mass range of m/z 35-450 in 0.45 s. The system was computer-controlled using Agilent GC-MSD ChemStation. Compounds were identified by matching their mass spectra with the flavour spectral library with a resemblance percentage above 90 %. Results and Discussion Extraction yield and time The yields (in terms of g of essential oil/1 g of coriander seeds) of SWE under these conditions (0.6 -00.4%) of SWE were obtained at high temperature (150 °C) under both dthat there wep15 min for SWE) is clearly advantageous for the SWE method. Composition of essential oil For SWE extraction of coriander seeds, experiments were performed at different combination of extraction pressure and temperature. Identification of compounds extracted using these techniques were performed by GC-MS. Figure 1 shows the total ion current (TIC) chromatogram of coriander seed extract obtained using the two meth

lyl butyrate and geraniol. Comparison in the composition of coriander extracts obtained using various extraction techniques is shown in Table 1.

Table 1. Compounds (%)* extracted from coriander by HD and SWE under different conditions. Compound HD SWE 1

(870 psi, 65 ˚C)

SWE 2 (870 psi, 100 ˚C)

SWE 3 (870 psi, 150 ˚C)

SWE 4 (1000 psi,

65 ˚C)

SWE 5 (1000 psi, 100 ˚C)

SWE 6 (1000 psi, 150 ˚C)

Linalool 66.5 87.8 87.7 68.7 88.6 85.4 79.5 Isoborneol 6.8 6.1 3.8 0.8 6.1 2.9 4.3 Citronellyl butyrate 13.4 2.2 1.2 3.7 1.6 1.4 1.3 Geraniol 13.3 4.0 7.3 26.8 3.6 10.4 14.9

*Percent of component based on area normalization.

43


(a) (b)

Figure 1. Total ion current (TIC) chromatograms of compounds of coriander seeds extracted by SWE (a) and HD (b).

In general, the relative amounts of the major compounds obtained using HD and SWE under different conditions are comparable. Linalool is the most abundant composition of coriander isolated either by

or the under different pressures but same temperature ie. SWE 1 vs SWE 4 and SWE 2 vs

that the coriander extracts obtained using SWE produced a pleasant odor

dgement

SWE under all conditions (68.7-88.6%) and HD (66.5%). However, the relative amount of citronellyl butyrate obtained using SWE is slightly lower than those obtained using hydrodistillation. For SWE, a change in extraction temperature resulted in a slight change of composition of the extracted oil. The percentage of geraniol increases with temperature while the percentage of linalool and isoborneol decreases at high temperature. Therefore using SWE, specific composition of essential oils can be obtained by optimizing the extraction temperature. Extraction pressure however did not seem to give significant effect on the oil composition as shown by the similarity of the oil composition fextracts obtainedSWE 5. It is noteworthysimilar to the starting plant material. Conclusions The use of SWE has shown to be a good alternative for the extraction of essential oils. Essential oil of coriander obtained using SWE (at temperature 65-150 ˚C and pressure 870-1000 psi) was comparable to that obtained from hydrodistillation. SWE enables rapid extraction and has the advantage of being selective because it is possible to manipulate the extract composition under a given working conditions. Acknowle The authors would like to acknowledge financial support from IRDC, Universiti Teknologi Mara for funding this project (IRDC Project number: 600-IRDC/ST 5/3/744). References

[1] Khajeh, M., Yamimi, Y., Bahramifar, N., Sefidkon, F., Pirmoradei, M.R. (2005) “Comparison of

essential oils compositions of Ferula assa-foetida obtained by supercritical carbon dioxide extraction and hydrodistillation methods” Food Chemistry. 91. 639-644.

44


[2] Diaz-Maroto, M.C., Pérez-Coello, M.S., Cabezudu, M.D., (2002) “Supercritical carbon dioxide extraction

l Bioanal Chem. 379. 1127-1133. [6] So Ayala, R., Luque de Castro, M.D. (2001) “Continuous subcritical water extraction as a useful tool

. 109-113.

of volatiles from spices. Comparison with simultaneous distillation-extraction” J. Chromatogr. A. 947. 23-29.

[3] Lucchesi, M.E., Chemat, F., Smadja, J., (2004) “Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distilation” J. Chromatogr. A. 1043. 323-327.

[4] Ozel, M.Z., Gogus, F., Lewis, A.C. (2003) “Subcritical water extraction of essential oils from Thymbra spicata” Food Chemistry. 82. 381-386.

[5] Ozel, M.Z., Gogus, F., Kaymaz, H. (2004) “Superheated water extraction, steam distillation and Soxhlet extraction of essential oils of Origanum onites” Ana

tofor isolation of edible essential oils” Food Chemistry. 75

45


ANALISIS TOLUENA RESIDU DALAM PEMBUNGKUS MAKANAN DENGAN KAEDAH PENGEKSTRAKAN RUANG KEPALA KROMATOGRAFI GAS

ng Chin1 and Mohd Marsin Sanagi2

Abstrak. Bahan polimer banyak digunakan sebagai bahan pembungkusan makanan. Toluena residu yang tertinggal di dalam bahan pembungkusan boleh meresap masuk ke dalam makanan yang dibungkus dan seterusnya menjejaskan kualiti makanan. Dalam kajian ini, penganalisisan ruang kepala yang manual telah berjaya direkabentuk dan dibangunkan. Penentuan kepekatan toluena residu dilakukan dengan kaedah penambahan piawai dan kaedah pengekstrakan ruang kepala berbilang (MHE) menggunakan kromatografi gas-pengesan pengionan nyala (GC-FID). Pengenalpastian toluena dilakukan dengan perbandingan masa penahanan toluena piawai dan GC-MS. Kajian mendapati suhu pemanasan yang paling sesuai ialah 180 oC dengan masa optimum ialah 10 minit. Kajian juga menunjukkan sampel berbilang warna mempunyai kepekatan toluena residu yang lebih tinggi berbanding sampel satu warna. Sampel yang dianalisis dengan kaedah penambahan piawai didapati mempunyai kepekatan toluena residu yang lebih tinggi berbanding dengan kaedah MHE. Tetapi, perbandingan dengan kepekatan toluena residu yang diperoleh daripada makmal De'Paris, Perancis mendapati bahawa sampel berkepekatan rendah yang dianalisis dengan kaedah MHE mempunyai peratus ketepatan yang tinggi. Sementara itu, sampel berkepekatan tinggi pula mempunyai peratus ketepatan yang rendah disebabkan oleh ralat bersistem. Perbandingan kaedah penentuan toluena mendapati kaedah MHE adalah lebih presis berbanding dengan kaedah penambahan piawai.

Abstract The presence of residual toluene in this fheadspac

But, com with the results obtained from De'Paris laboratory, France found that MHE method gave higher accuracy as obtained for sample with high een determination methods showed

pembungkusan makanan, kromatografi gas

Pengenalan Pembungkusan merupakan suatu proses yang tersusun untuk menyediakan barangan bagi tujuan pengangkutan, pengedaran, penyimpanan, pemasaran dan penggunaan akhir. Kini, bahan pembungkusan bertindak sebagai alat komunikasi untuk membolehkan pengguna mengenalpasti produk atau jenama yang baru, mengetahui kandungan nutrient yang hadir dan dalam sesetengah kes, bahan pembungkus memberi maklumat tentang cara penyediaan makanan tersebut. Pembungkus fleksibel seperti lamina mengandungi beberapa lapisan filem dan pelarut toluena biasanya digunakan dalam percetakan grafik pada filem ini.

Perhatian perlu diberikan kepada bahan pembungkus apabila terdapat kemungkinan berlakunya keracunan makanan yang disebabkan oleh resapan bahan pencamar ke dalam makanan semasa pemyimpanan makanan. Peresapan bahan ini mempunyai kesan dari segi kualiti dan ketoksikan makanan. Ia mungkin mempunyai bau dan boleh memberi kesan kepada rasa makanan. Keadaan sebaliknya seperti penyerapan rasa makanan oleh pembungkus juga boleh mengurangkan intensiti bukan ahaja m an malahan ia mungkin membawa kesan negatif ke atas kesihatan

Lim Yi

1INTEC, Universiti Teknologi MARA Section 17 Campus, 40200 Shah Alam, Selangor. 2Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor.

Tel: 607-55227155, Fax: 607-55227109, e-mail: [email protected]

Polymeric materials are used in many food contact applications as packaging material..

ood packaging material can migrate into food and thus affect the quality of food. In this study, a manual e analysis was successfully designed and developed. The determination of residual toluene was carried out with

standard addition method and multiple headspace extraction (MHE) method using gas chromatography-flame ionization detector (GC-FID). Identification of toluene was performed by comparison of its retention time with standard toluene and GC-MS. It was found that the suitable heating temperature was 180 oC with an optimum heating time of 10 minutes. The study also found that the concentration of residual toluene in multicolored sample was higher compared to monocolored sample whereas residual toluene in sample analyzed using standard addition method was higher compared to MHE method.

parisonfor sample with low analyte concentration. On the other hand, lower accuracy wconcentration of residual toluene due to the systematic error. Lastly, comparison betwthat MHE method is more precise compared to standard addition method.

ata kunci: pengekstrakan ruang kepala, bahan K

rasa makanan dan aroma makanan. Bahan pencemar dalam pembungkus makanansp

enjejaskan kualiti makanengguna sekiranya kepetan bahan pencemar melebihi had kepekatan yang dibenarkan.

Kajian ini melibatkan perekabentukan dan pengubahsuaian penganalisisan ruang kepala yang manual. Dalam kajian ini, suhu dan masa pemanasan dioptimumkan dan seterusnya kuantiti toluena residu akan ditentukan menggunakan kaedah penambahan piawai dan kaedah pengekstrakan ruang

46


u warna dan berbilang warna alam 6 jenis pembungkus makanan.

Alat radVial jenis ruang kepala de × 32 mm) Supelc enutup pembebasa s aluminium yang mempunyai septum de is jen FE y 20 mm dan penutup yang mempunyai septum teflon (11 mm) juga daripada Supelco, , PA, U ntik jenis kedap uda ngan s keluara , Reno, SA. Pen ap udara

ang bersaiz 1 mL pu a SGE, Crimper ng dapat dilaraskan bukaan iznya jenis 20 mm dan

nalisis toluena residu dijalankan dengan menggunakan kromatografi gas Hewlett Packard model 890 GC dengan pengesan pengionan nyala (FID). Turus pemisahan yang digunakan ialah turus

Packard, USA. Turus yang berukuran 30 m

Enam jenis pembungkus yan MCP, PM, TC dan PD bangkan oleh Kilang BBM Sdn. Bhd., a untuk membentuk b t. Bl el yang pad s ketat dengan kerajang aluminium yang mempunyai ketebalan 30 - ah di antara luas spesimen (dalam cm ipadu vial (dalam mL) d an pad 15-20 ke an sampel dikeluarkan daripada "blok" samp npa memisahkannya. Setelah mengeluarkan rang-kura satu lapi pingan samp ipada ba atas blok kepingan sa l yang seterusnya diambil dan spesimen dipo enggun mplat. Spesimen itu digulung d imasukkan ke dalam vial dengan segera. Sel vial dit ngan cepat menggunakan crim angan. Prosedur

kepala berbilang (MHE) menggunakan kromatografi gas-pengesan pengionan nyala (GC-FID). Perbandingan kepekatan toluena turut dilakukan di antara sampel satd

EKSPERIMEN Reagen Larutan piawai toluena (99 %) daripada keluaran J. T. Baker, Phillipsburg, USA. Heksana (95 %) gred GC diperoleh daripada Fisher Scientific, New Jersey, USA. Hidrokarbon piawai, nonana (C9H20) adalah gred analar daripada jenama BDH, England. Gas helium pula dibekalkan oleh Syarikat MOX, Pasir Gudang, Johor.

as ngan bukaan luas × 46 mm) dan 2 mL (12 mmbersaiz 10 mL (22.5 mm

daripada o, Bellefonte, PA, USA. P n tekanan jeningan pelap is silikon / PT ang bersaiz

Bellefonte SA. Penyura de aiz 100 µL n Hamilton Nevada, U yuntik ked

y la daripad Australia. tangan yasa decapper tangan jenis 20 mm yang digunakan untuk membuka penutup vial ruang kepala pula adalah keluaran Kimble Glass Inc, Vineland, NJ, USA.

Instrumentasi A6rerambut Ultra 1 (dimetilpolisiloksana) keluaran Hewlettini berdiameter 0.25 mm dengan ketebalan filem 0.17 µm. Dalam kajian ini, helium digunakan sebagai gas pembawa pada kadar alir 2 mL/min. Suhu liang suntikan pada 150oC dan suhu pengesan ialah 250oC. Suhu GC isoterma digunakan pada 150 oC dan masa analisis yang diperlukan adalah 5 minit. Gas ruang kepala (1 mL) disuntik dengan menggunakan mod suntikan berpecah 1 : 10.

Pensampelan g digunakan dalam kajian ini iaitu sampel TE, CCB,

Tam or. SampC disum poi, Johat ini dibungku

el diletakkan bersamlok yang pada ok samp

40 µm. Nisba 5.

2) terhadap isitetapk Sebanyak ping

el ta seku n gnya san keel dar hagian sampel, mpe

tong m akan te an depas itu, utup de per t

Dalam kajian ini, dua kaedah digunakan dalam penentuan kuantitatif toluena residu iaitu kaedah penambahn piawai dan kaedah MHE. Kedua-dua kaedah ini merupakan kaedah piawai seperti yang tercatat dalam EN 261 WI 190. Dalam pengoptimuman parameter dalam pengekstrakan ruang kepala, suhu penyuntik kedap udara ditetapkan pada 100 oC dan suhu pemanasan vial yang mengandungi sampel ditetapkan pada 180 oC. Sampel dipotong, dimasukkan ke dalam vial dan ditutup dengan segera. Botol sampel bersama dengan sampel dipanaskan pada 180 oC selama 2, 5, 10, 15 dan 20 minit ± 10 saat. Dalam pengoptimuman suhu pemanasan, botol sampel bersama dengan sampel dipanaskan pada 100,120, 140, 160 dan 180 oC berdasarkan masa pengoptimuman yang diperoleh. Gas ruang kepala disuntik dan dianalisis dengan GC-FID.

47


Kaedah penambahan piawai Dalam kaedah penambahan piawai, sebanyak 5 vial disediakan. Spesimen yang disediakan (10 cm × 5 cm) digulung dan dimasukkan ke dalam vial 10 mL. Vial ditutup dengan segera. Jisim vial bersama

ngan isipadu yang meningkat (0-4 µL) disuntik ke

an penyunt yang telah dip o

Kaedah pengekstrakan ruang kepala berbilang (MHE) Kaedah MHE yang digunakan adalah secara piawai . Kaedah ini melibatkan 2 bahagian iaitu penentuan faktor gerak balas dan seterusnya penentuan toluena residu dalam sampel. Dalam penentuan faktor gerak vial 10 mL yang tertutup ditimbang. Sebanyak 1 µL larutan piawai toluena disuntik ke dalam vial yang tertutup d vial ditimbang sekali lagi untuk mendapatkan jisim 1 µL larutan toluena. Kemudian arutan nonana (piawai dalaman) disuntik

vial m eza. Sekali lagi, vial ditimbang untuk mendapatkan al dipanaskan pada suhu 180 C selama 10 minit. Analit dalam fasa gas disuntik ke

dalam G

fasa gas disuntik ke alam GC-FID dengan menggunakan penyuntik kedap udara 1 mL yang telah dipanaskan pada 100 oC

terlebih dahulu. Vial yang masih panas ke oses pembebasan tekanan. Dalam proses

ling opti seimbangan toluena antara fasa gas dan fasa pepejal telah tercapai.

aripada Rajah 1 juga, didapati masa pemanasan yang lebih lama iaitu selama 15 minit dan 20 minit

sampel ditimbang. Seterusnya, larutan piawai dedalam vial yang telah tertutup melalui septum.Setiap vial ditimbang untuk mendapatkan jisim larutan piawai yang telah ditambah. Semua vial dipanaskan pada suhu 180 oC selama 10 minit secara berterusan. Analit dalam fasa gas itu (1 mL) kemudian disuntik ke dalam GC-FID menggunak

ik anaskan pada suhu 100 C.

dalaman

balas, an kemudian, 1 µL l

ke dalam enggunakan penyuntik yang berbojisim nonana. Vi

C-FID dengan menggunakan penyuntik kedap udara 1 mL yang telah dipanaskan pada 100 oC terlebih dahulu. Dalam penentuan toluena residu dalam sample, vial yang mengandungi spesimen ujian ditimbang. Kemudian, 1 µL larutan nonana disuntik ke dalam vial menerusi septum menggunakan penyuntik dan vial ditimbang semula untuk mendapatkan jisim larutan nonana yang disuntik. Vial dipanaskan pada suhu 180oC selama 10 minit. Analit (1 mL) dalamd

mudian melalui prini, satu jarum yang telah disambung ke sumber gas helium dimasukkan ke vial melalui septum vial dan satu lagi jarum terus dicucuk ke dalam vial. Gas helium dialirkan pada kadar alir 15 mL/minit selama 1 minit ± 10 saat. Selepas itu, kedua-dua jarum dikeluarkan daripada vial dan vial dimasukkan semula ke dalam ketuhar. Untuk pengekstrakan kali kedua dan seterusnya, langkah pemanasan vial, analisis GC dan proses pembebasan tekanan diulang untuk vial yang sama sebanyak 4 kali.

Keputusan dan perbincangan

Pengoptimuma masa pengekstrakan Daripada Rajah 1 yang ditunjukkan, didapati luas puncak toluena tidak memberikan perbezaan yang ketara pada masa pemanasan 2 minit dan 5 minit. Ini disebabkan kedua-dua tempoh masa ini terlalu singkat untuk toluena mencapai keseimbangan antara fasa gas dan fasa pepejal dalam vial tertutup.

Rajah 1: Luas puncak toluena melawan masa pemanasan (minit)

Sebaliknya, masa pemanasan selama 10 minit merupakan masa pengestrakan yang pa

mum. Ini menunjukkan keD

0Lua

1 0 pun 2 0

c (p

3 04 05 0

ak to

luen

a

A)

6 0

0 5 1 0 1 5 2 0 2 5M a s a ( m in it )

s

48


memberikan luas puncak toluena yang semakin menurun. Dalam erti kata yang lain, masa pemanasang lama akan mengganggu keseimbangan fasa toluena dalam vial. Deng

nasan

enDaripada Rajah 2, ia jelas menunjukkan luas puncak toluena adalah berkadar langsung dengan suhu pemanasan iaitu semakin tinggi suhu pemanasan yang digunakan, semakin tinggi luas puncak toluena yang diperoleh. Ini menunjukkan suhu 180oC merupakan suhu yang paling sesuai.

Rajah 2: Luas puncak toluena melawan suhu pemanasan Suhu pengekstrakan melebihi 180 oC tidak digunakan disebabkan kekangan penganalisian

ruang kepala. Septum pada tudung aluminium mungkin akan lebur pada suhu yang terlalu tinggi. Selain itu, pemegangan vial yang telah dipanaskan pada suhu yang tinggi, contohnya 200 oC adalah sukar walaupun sarung tangan digunakan. Dengan ini, suhu 180 oC dipilih sebagai suhu pengesktrakan yang paling sesuai dan digunakan dalam analisis ruang kepala dalam kajian seterusnya.

Pengenalpastian sebatian toluene secara masa penahanan dan GC-MS Dalam kajian ini, masa penahanan toluena adalah 2.653 minit dan ia hampir sama dengan masa penahanan toluena piawai (Rajah 3).

Rajah 3: Pemisahan GC bagi sebatian Rajah 4: Kromatogafi ion toluena dalam sample

Analisis GC-MS telah dilakukan untuk mengenalpasti puncak toluena dan puncak sampingan yang terhasil apabila penyuntik dipanaskan. Kromatografi ion jumlah seperti yang ditunjukkan dalam Rajah 4 menunjukkan kehadiran 2 puncak dengan tertib pengelusian yang sama. Puncak 2 dapat dikenalpasti

yan an ini, masa pemaselama 10 minit dipilih sebagai masa pemanasan yang paling optimum.

goptimuma suhu pengestrakan P

05

1 01 52 02 53 0

8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0

S u h u ( o C )

Luas

pun

cak

(pA

)

FID

minit

Toluen

Kelimpahan

Masa

49


seba ada pa Perbandingan kepekatan toluena residu antara kaedah penambahan piawai dan kaedah MHE Perb ya dapat dilakukan ke atas 3 jenis sampel sahaja iaitu sampel TC, PM dan MCM. Perbandingan ke atas sampel CCB, TE dan ri kelompok sampel yang sama untuk dianalisis d nunjukkan kepekatan toluena residu yang ing dengan kaedah MHE. Ini mungkin d dalam sampel perlu dibuat sebelum analisis sampe n piawai. Dengan erti kata lain, anggaran toluen

Jadual 1: Perbandingan kepe iawai dan kaedah MHE

Kepekatan toluena (mg/m2)

gai puncak toluena. Perbandingan spektrum jisim toluena dengan spektum jisim toluena daripngkalan data Wiley memberika kebarangkalian yang melebihi 90 %.

andingan kepekatan toleuan residu antara kaedah penambahan piawai dan kaedah MHE han

PDC tidak dapat dilakukan disebabkan kehabisan sampel daengan kaedah MHE. Jadual 1 jelas me

ditentukan melalui kaedah penambahan piawai adalah lebih tinggi berbandisebabkan anggaran kuantiti toluena residu

l sebenar dilakukan menggunakan kaedah penambahaa residu mempengaruhi keputusan analisis.

katan toluena residu ant ra kaedah penambahan pa

Sampel Kaedah penambahan piawai Kaedah MHE satu warna berbilang warna Satu warna berbilang warna

TC 15.55 ± 2.16 18.33 ± 1.14 5.09 ± 0.27 7.21 ± 0.18 PM 10.78 ± 1.57 16.82 ± 1.02 2.81 ± 0.17 4.53 ± 0.13

MCM 8.32 ± 1.12 12.09 ± 1.09 4.19 ± 0.15 5.89 ± 0.15 Ujian awal mendapati anggaran kepekatan toluena residu adalah sekitar 8 mg/m2. Oleh itu, kepekatan toluena residu yang ditentukan melalui kaedah penambahan piawai adalah lebih tinggi nilainya. Sebaliknya, anggaran sebegini tidak perlu dilakukan dalam kaedah MHE. Analisis toluena residu dilakukan secara terus secara pengekstrakan berterusan dalam kaedah MHE. Perbandingan kepekatan toluena residu antara makmal Dalam kajian ini, perbandingan kepekatan toluena residu telah dilakukan di antara makmal

endapatkan bahan rujukan piawai bagi sampel bahan pembungkusan.

Peratus ketepatan (%)

disebabkan kesukaran untuk mPerbandingan keputusan analisis antara makmal dilakukan bertujuan untuk mengatasi ketakpastian kaedah dan seterusnya meningkatkan kebolehpercayaan hasil analisis. Bagi sampel TC, PM dan MCM, perbandingan kepekatan toluena residu telah dilakukan di antara makmal UTM dan makmal Dannone, Paris seperti yang ditunjukkan dalam Jadual 2.

Jadual 2: Perbandingan kepekatan toluena residu antara makmal

Makmal UTM Sampel MakmaKaedah MHE Kaedah

penambahan piawai

Dannone, Paris Kaedah MHE Kaedah penambahan piawai

l

TC 1 7.2114 18.3280 6.2 116.31 295.61 TC 2 5.0876 15.5480 6.2 82.06 250.77 PM 1 4.5293 16.8200 10.7 42.33 157.20 PM 2 2.8100 10.7766 10.7 26.26 100.72

MCM 1 5.8890 12.0946 11.1 53.05 108.96 MCM 2 4.1859 8.3186 11.1 37.71 74.94

Daripada Jadual 2 yang ditunjukkan, dapat diperhatikan bahawa kepekatan toluena residu

alam sampel TC d yang dianalisis dengan kaedah MHE mempunyai peratus ketepatan yang baik iaitu 116.31 % berbanding dengan kaedah penambahan piawai. Sebaliknya, untuk el MCM pula, kaedah penambahan piawai didapati mempunyai peratus

ng rendah iaitu kurang daripada 10 mg/m2.

sekitar 82.06 % hinggasampel PM dan sampketepatan yang lebih baik iaitu di sekitar 74.94 % hingga 157.20 % berbanding dengan kaedah MHE. Corak peratus ketepatan yang dapat diperhatikan ialah sampel dengan kepekatan toluena residu yang tinggi iaitu melebihi 10 mg/m2 apabila dianalisis dengan kaedah penambahan piawai memberikan peratus ketepatan yang tinggi berbanding dengan kaedah MHE. Keadaan sebaliknya diperhatikan

ntuk sampel dengan kepekatan toluena residu yau

50


disebabkan nilai anggaran kepekatan toluena residu dalam sampel yang dianalisis dengan kaedah penambahan piawai ditetapkan pada nilai kepekatan yang agak tinggi iaitu 8 mg/m2.

Perbandingan kaedah penentuan toluena residu Perbandingan kaedah dilakukan bertujuan untuk menguji sama ada kaedah MHE dan kaedah penambahan piawai berbeza dari segi kejituan iaitu sama ada perbezaan dua sisihan piawai bererti.

Jadual 3 : F bagi sampel TC, PM dan MCM kiraan

Kaedah Sampel

MHEpiawai Penambahan

TC 1 41.1555 TC 2 62.0135 PM 1 58.4552 PM 2 84.0046

MCM 1 50.3499 MCM 2 59.6905

*Daripada jadual F, F2,2 = 39.00

Daripada Jadual 3, dapat diperhatikan bahawa Fkiraan bagi sem a sampel adalah lebih besar daripada Fjadual. Ini menunjukkan terdapat perbezaan bererti antara sisihan piawai kaedah MHE dan

dah penambahan piawai lebih aka dapat disimpulkan bahawa

kaedah MHE adalah lebih presis dalam penentuan toluena residu dalam sampel.

suhu pemanasan yang paling s

epekatan toluena residu yang rendah (kurang daripada 10 mg/m ), analisis toluena residu m

etepatan yang rendah diperoleh iaitu di antara 26.3 % hingga 53.1 %. Ini mungkin disebabkan terdapatnya ralat sistematik dalam kerja analisis yang menyebabkan perbezaan kepekatan

ng sama.Ujian F yang digunakan dalam perbandingan kaedah

Mar

Packaging and Their Migration into Tena Sugar." Food Addit. Contam. 16(12). 571-577. Aur erhjelm, L. (2001). "Migration of alkilbenzenes from packaging into Food and Tenax."

u

kaedah penambahan piawai pada aras 5 %. Oleh kerana varians kaebesar daripada varians kaedah MHE pada 5 % aras kebarangkalian, m

KESIMPULAN

Dalam kajian ini, kaedah pengekstrakan ruang kepala menggunakan analisis GC-FID dapat diaplikasikan dalam analisis toluena residu. Toluena terelusi dalam masa kurang daripada 3 minit. Didapati masa pemanasan yang paling optimum adalah 10 minit sementara

esuai pula ialah 180 oC. Kajian yang dilakukan menunjukkan bahagian berbilang warna dalam sampel pembungkus yang dianalisis dengan kaedah penambahan piawai mahupun kaedah MHE memberikan kepekatan toluena yang lebih tinggi berbanding dengan bahagian satu warna. Bagi sampel dengan k 2

enggunakan kaedah MHE mempunyai peratus ketepatan yang baik iaitu sekitar 82.1% hingga 116.3 %. Sebaliknya, untuk sampel sampel dengan kepekatan toluena residu yang tinggi (melebihi 10 mg/m2), peratus k

toluena residu dalam sampel yapenentuan toluena residu menunjukkan kaedah MHE adalah lebih presis dalam penentuan toluena residu dalam sampel. Rujukan 1. Paine, F. A. (1990). "The Packaging User's Handbook." London: Blackie and Son Ltd. 4-7.

Crosb2. y, N. T. (1981). "Food Packaging Materials." London: Applied Science Publishers. 9-11, 43-47. 3. sihi, R. (1993)."Testing Packaging Material : Why and How". Weeks Publishing Company. 4. Oswin, C. R. (1975). "Plastic Films and Packaging" London: Applied Science Publishers Ltd. 20-21. 5. Hotchkiss, J. H. (1988). "Food and Packaging Interactions." Washington, D. C.: American Chemical Society. 1-9. 6. Vermeiren, L., Devlieghere, F., Beest, M. V., Kruijf, N. and Debevere, J. (1999). “Developments in the Active

Packaging of Foods.”Trends in Food Sci & Technol. 10. 77-86. 7. Aurela, B., Kulmala, H and Soderhjelm, L. (1999). "Phthalates in Paper and Board

x and8. ela, B, Ohra-aho, T and Sod

Packag. Technol. Sci. 14. 71-77. 9. Korbo, L., Ladefoged, O., and Lam, H. R. (1996). "Neuronal Loss in Hippocampus in Rats Exposed to Toluene."

Neurotoxicology .17(2). 359-66.

51


10. Ono, A., Sekita, K., and Ogawa, Y. (1996). "Reproductive and Developmental Toxicity Studies of Toluene : Effects of nha in Rats." J Environ. Pathol. Toxicol. Oncol. 15(1). 9-20. ud

action." J. Chromatogr. A. 204. 371-376.

I lation Exposure on Fertility11. G at, A. E. and Brillante, S. M. (1996). "Mutiple Headspace Extraction Capillary Gas Chromatography for the

Quantitative Determination of Volatiles in Solid Matrices." U.S.A: Agilent Technologies. 12. Kolb, B and Pospisil, P. (1981). "Quantitative Analysis of Residual Solvents in Food Packaging Printed Film by

Capillary Gas Chromatography With Multiple Headspace Extr

52


SYNTHESIS OF 3-O-SUCCINYL-BETULINIC ACID AS ANTI –CANCER AGENTS AGAINST HUMAN MYELOID LEUKAEMIA AND HUMAN T-4 LYMPHOBLASTOID

CELLS LINE

Mohd Tajudin Mohd Ali a,Faujan Ahmad b,, Abdul Manaf Ali c, and Nurhana Faujan d

a Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia.

culty of Science tal Studies, Universiti Putra Malaysia, 43400 UPM Sela alaysia.

c Faculty of Biotechnology and lecular Sciences d Institute of Bioscience, Universiti Putra Malaysia

* Corresponding author 603-55 Fax : +603-55444566 email : t ali@sala .edu.my

Abstrac tulinic acid was esterified with succi hydride in the presence of anhydrous pyridine. Optimization studies on the esterification reaction were carried out. The effect of varying paramet uch as the mole ratio, te ture and time course was investigated. The optimal conditions for synthesizing 3-O-succiny inic acid were obtained by refluxing betulinic acid and succinic anhydride in 1:8 ratio with the presence of 5 ml anhydrous pyridine for 24 hours at a temperature of 115oC. The percentage c ion as detected by gas chromatography analysis was 53.5%. totoxic study also revealed that 3-O nyl-betulinic acid was more potent than betulinic acid in inhibiting human m leukem L 60) and human T-4-lmphoblastoid (CEMS line with IC50 values were 1.3 µg/ml a Keywor erification, betulinic acid, nic acid

1 duction The lup acyclic triterpene ic acid β-hydroxy-lup-20(29)-ene-28-oic, was isolated higher plants. Betulinic acid has been reported to possess anti-tumor activity towards cultured n melanoma cell in vitr ivo m Other biological activities reported for betulinic acid include anti-inflammatory activity2 and inhibition of phorbol ester-induced epidermal ornithin rboxylase accumulation he mou with subsequent inhibition of the carcinogenic response in the two- stage –skin m ic acid has three active sites at C-3, C-20 and C-28 , where modifications can be performed to yield derivatives. Modification of betuli volving the esterification reaction was reported. Note that 3-O-succinyl-betulinic acid was reported in literature; obtained by allowing betulinic acid and succinic anhydride in the presence hydrochloric acid as a acid catalyst (Fujioka st is expected to promote attack of a nucleophilic oxygen betulinic acid on the carb arbon of the anhydride by protonation of the carbonyl oxygen.

work, betulinic cid ester was synth using betulinic acid and succinic anhydride in Scheme 1. The effect of mole ratio, time and temperature of the reaction was investig 2 mental

ials ic acid was extracted from Malaysia Succinic anhydride was purchased from

performed on Kieselgel 60 F254 plates t graphy was carried out with silica gel (Merck, code number: a tical grade.

b Fa and Environmen Serdang, ngor, M

Biomo

: Tel: + 435735ajudin m.uitm

t: Be nic an

ers s mperal-betul

onversThe cy -succi

yeloid ia (HS) cells nd 1.3 µg/ml, respectively.

ds: Est betuli ester Intro

ane type pent betulin (1), 3- from huma o and v odel1 .

e deca in t se-ear 3mouse odel .

Betulinnic acid in

to react et al., 1994). The role of the acid catalyof the onyl c In this a esized

ated.

ExperiMater2.1

Betulin n higher plants. hy (TLC) wasSigma Chemical Co. Thin layer chromatograp

(0.2 mm thick. Merck). Column chroma o1.07734.1). Other chemicals were of an ly

53


C O O H

H O

P y r i d i n e ,C

R e f l u x e d

O

H 2 C

H C2 C

O

C O O H

OC

O

H 2 C

H 2 C C

O

O H

Scheme 1 : Reaction of betulinic acid and succinic anhydride

2.2 Esterification of betulinic acid ester.

Betulinic acid (100.0 mg, 0.22 mmole) and succinic anhydride (175.4 mg, 1.32 mmole) in anhydrous pyridine (5 ml) were refluxed for 24 hours. The reaction mixture was then acidified with 0.75 M hydrochloric acid (10 ml) The product was extracted with chloroform (2 x 30 ml) and dried over moleculer seive. The solvent was then removed using Rotary Evaporator.

The compounds were detected by TLC analysis using chloroform as a solvent and detected under iodine vapour. Detection of the ester product was made by comparing with the Rf values of betulinic acid and succinic anhydride spots on TLC plate which were developed by the same solvent system.

The crude product was chromatographed on silica gel ( code number: 1.07734.1000) column chromatography (3 cm, i.d. and 30 cm length) using chloroform as the eluting solvent to afford the desired product.

2.3 Analysis of the product

oC and 320oC. Helium was used as the carrier gas with a pressure of 37Kpa. The initial temperature of the column was 60oC which was run

erature was increased with a flow rate of 20 deg./min. up to 200oC for 3 C for 3 minutes.

was studied using JOEL nuclear magnetic resonance model ECA-400.

The effect oinvestigated on the number of mole of ester produced by GC analysis.

The ester product was analyzed by thin layer chromatography (TLC) and developed in the mobile phase of chloroform. The purified product was also analyzed using a gas chromatograph (GC-17A, Schimadzu) equipped with BPX5 column (0.25mm, ID and 30m length). Both of non-split /splitless injector and detector were set at temperatures of 280

for 3 minute. The tempminutes, then up to 320o

The percentage conversion was determined by using mixtures containing betulinic acid, succinic anhydride and betulinic acid ester. Infrared analysis was carried out using Perkin- Elmer Fourier transform infrared model 1650 while mass spectrum of the product was studied using Shimadzu gas chromatography –mass spectroscopy (GC-MS, model 7A). The structure of the product

2.4 Effect of mole ratio

f various molar ratio of betulinic acid/ succinic anhydride (1:2, 1:4, 1:6, 1:8, 1:10) was . The percentage conversion of ester was calculated based

54


2.5 Effect of time

The reaction mixture was refluxed in anhydrous pyridine (5 ml) at different reaction time i.e. 8, 16, 24, 32 and 48 hours respectively. The percentage conversion of ester was calculated based on the number of mole of ester produced by GC analysis. 2.6 Effect of temperature

The reaction mixture was heated in anhydrous pyridine (5 ml) at o

different temperatures i.e. 37, 85 and 115 C, for 24 hours using oil bath. The percentage conversion of ester was calculated based on the number of mole of ester produced by GC analysis. 3. RES CUSSIONS

nalysis of tas identified as 3-O-

IR (cm-1) had max 3402(OH), 2948 (CH2), 1812 (C=O :ester), 1734 (C=O : acid), 1248 (C-O), 886 (C=C) cm-1; 1H MR (CDCl3) ; δ 0.86 (s,3H), 0.87 (s,3H), 0.88 (s,3H), 0.99 (s,3H), 1.00 (s,3H), 1.70 (s,3H), 3.52 (q,

H-19), 4.50 (dd,H-3), 4.65 (s,1H,H-29), 4.75 (s,1H,H-29) , 2.06 (s,2H,C-32), 2.26 (s,2H,C-33); 13C DCl3) ; δ 38.7 (C-1), 26.0 (C-2), 81.2 (C-3), 38.2 (C-4), 55.7 (C-5), 18.4 (C-6), 34.5 (C-7), 41.0 (C-

8), 50.9 (C-9), 37.4 (C-10), 21.6 (C-11), 23.9 (C-12), 38.1 (C-13), 42.7 (C-14), 30.0 (C-15), 31.8 (C-17), 49.5 (C-18), 46.7 (C-19), 150.1 (C-20), 30.5 (C-21), 36.5 (C-22), 28.1 (C-23),16.7

(C-24), 16.5 (C-25),16.3 (C-26), 16.2 (C-27), 181.2 (C-28), 110.3 (C-29), 19.6 (C-30), 167.4 (C-31),

pectrum in d-chloroform, indicated the presence of six tertiary methyl groups sonated as singlets at δ 0.86 (s, 3H), 0.87 (s, 3H), 0.88 (s, 3H), 0.99 (s, 3H), 1.00 (s, 3H) and 1.70

(m, H) was due to the proton at C-19 of the betulinic acid skeleton and s at δ 4.65 (s, H) and δ 4.77 (s, H) were due

to methyelene proton o oup at C-29 position. The signals at δ 2.06 and δ 2.26 were due inyl group. This data is summarized in Table 6. It is in agreement with the spectra

f C-20

signaonthy

Otherwith t

13

m

asu

value he action of betulinic acid with succinic anhydride, the optimum mole ratio was at 1:8, with nversion percentage at 32.9%.

t, after the optimum mole ratio has been achieved , the conversion percentages started to decrease. These results were due to the fact that large quantity of the acid

used was blocked the attacks of the nucleophilic oxygen of betulinic acid at C-3 position on the

ULT AND DIS

A The purified product was analyzed using spectroscopic method and w

he product

succinyl-betulinic acid as white crystal (melting point: 278-280oC, 49.2% yield). It had νN

(C

16), 57.9 (C-

30.7 (C-32), 32.4 (C-33), 171.3 (C-34). MS; m/z 556 (M+), 511, 483, 438, 423, 395, 248, 220 and 189. It’s 1H-NMR sre(s, 3H). The signals at δ 3.00δ 4.50 (dd, H) was due to the proton at C-3; while signal

f isopropenyl grto -CH2 from succdata reported by Fujioka et al.,(1994) and is compared with the expected values.

The 13C-NMR spectrum of 3-O-succinyl-betulinic acid showed the down field shifts oand C-29 which is the site of terminal double bond resonatiy at δ 150.1 and 110.3, respectively. The

l due to the carbonyl group of C-28 resonated at δ 181.2. The additional 13C-NMR signals ated at δ 167.4 and δ 171.3 were due res to carbonyl group of ester at C-31 and C-34. The

me lene proton of succinyl group at C-32 and C-33 resonated at δ 30.7 and 32.4 respectively. chemical shifts of 3-O-succinyl-betulinic acid are summarized in Table 1; and are in agreement he literature data Fujioaka T., et al (1994) . To the best of our knowledge this is the first 13C-

NMR data reported for 3- O -succinyl- betulinic acid . The comparison of this NMR data with the Che NMR programme are also included on the table.

The Rf values for betulinic acid, 3- O -succinyl-betulinic acid and succinic anhydride were red at 0.09, 0.33 and 0.83, respectively. The desired ester was expected tome have greater

polarity compared to betulinic acid.

Effect of mole ratio In all cases, the conversion percentage increased along with the mole ratio up to a certain

in which after that point, the conversion percentage started to decrease (Figure 1). In t re

coIt is noted tha

of the products

55


carbonyl carbon of the acid . At high mole of the substrates, the medium of reaction mixtures were ore viscous, thus achieving lower reaction rates and consequently with lower conversion

percentages.

13 ata of 3-O-Succinyl-betulinic acid and comparision to the assignment of

Carbon Betulinic acid1 Experiment2

m

Table 1 : The C-NMR dbetulinic acid

C-1 38.8 38.7 C-2 27.4 27.3 C-3 79.0 79.0 C-4 38.7 38.3 C-5 55.3 55.3 C-6 18.3 18.3 C-7 34.3 34.3 C-8 40.7 40.6 C-9 50.5 50.5 C-10 37.2 37.0 C-11 20.8 22.6 C-12 25.4 25.4 C-13 38.4 37.1 C-14 42.4 42.4 C-15 29.7 29.7 C-16 32.1 31.9 C-17 56.3 56.3 C-18 49.2 49.2 C-19 46.7 46.8 C-20 (C=C) 150.4 150.4 C-21 30.5 30.5 C-22 37.0 35.9 C-23 28.0 28.0 C-24 15.3 16.0 C-25 16.1 15.3 C-26 16.0 14.7 C-27 14.7 14.1 C-28 (C=O) 180.8 180.0 C-29 (C=C) 108.3 109.7 C-30 19.4 20.8 C-31 (C=O) 167.5 C-32 38.8 C-33 44.0 C-34 (C=O) 177.5 C-35 23.0 C-36 23.8

Note

1 Betulinic Acid

2 Experiment Value

56


-5

5

0 1/2 1/4 1/6 1/8 1/10

Mole Ratio ( mol betulinic acid / mol succinyl anhydride)

Perc

ent

15

25

45

age

of C

onve

%

:The effect mole ratio of substrates (betulinic acid / succinic anhydride ) on the

ation reaction of betulinic acid (Reaction time : 24 hours, Temperature : 115oC and

action of betulinic acid with succinyl dride was 1:8

version percentage creased up to the optimum value at 24 hour reaction before starting to decreased and its optimum

s at 53.5 %. After achieving the optimum point, the conversion percentages seemed to may be due to the water excessive production during the esterification reaction and

35rsio

n (

Figure 1sterifice

0.062mole Pyridine)

Effect of time

Figure 2, shows the time course for the esterification reanhydride. The mole ratio used in the reaction of betulinic acid with succinic anhy

hich conversion percentage at 47.3% at the 8 hour reaction time. The conwinconversion waecrease. Thisd

caused the reverse hydrolysis reaction to occur.

0

10

20

30

40

0 8 16 24 32 40 48

Time (Hours)

Perc

enta

ge o

f Con

vers

ion

( %)

50

he effect of time on the esterifica

The reaction mixture consisted of betulinic acid (100mg), succinyl anhydride (192.1 mg) and anhydrous pyridine (5ml)

Figure 2: T tion of betulinic acid and succinic anhydride.

and temperature at 115oC.

57


Effect of temperature

The effect of temperature on the esterification reaction of betulinic acid with succinic anhydride shown in Figure 3. The percentage of conversion increased with increasing temperature and reached the maximum conversion percentage at 115oC (i.e. 29.8% yield).

05

101520253035404550

Perc

enta

ge o

f Con

vers

ion

( %)

igure 3: The effect of temperature on the esterification of betulinic acid and succinic

ml

The ell growths are summarized in Table 2.

0 37 85 115

Temperature (o C)

Fanhydride. The reaction mixture consisted of betulinic acid (100mg), succinic anhydride (192.1 mg) and anhydrous pyridine (5ml).

Cytotoxic Effects Betulinic acid inhibited human myeloid leukemia cell (HL60) with an IC50 values were 2.4 µg/and inhibited human T4-lymphoblastoid cell (CEMSS) growth with an IC50 value of 1.8 µg/ml. Onthe other hand, 3-O-succinyl-betulinic acid showed an inhibitory effects on human myeloid leukemia cell with an IC50 values of 1.3 µg/ml, while its IC50 for inhibition of human T4-lymphoblastoid cell growth was 1.3 µg/ml. These data indicated that 3-O-succinyl-betulinic acid is more potent than

the human myeloid leukemia and of human T4-lymphoblastoid cells.betulinic acid in inhibiting IC50 values against cancer c

Table 2 : Cytotoxic effects (µg/ml) for betulinic acid and 3-O-succinyl-betulinic acid.

a Concentration which inhibits human myeloid leukemia cell by 50%. b Concentration which inhibits human T4-lymphoblastoid cell by 50%.

Compound IC50a IC50

b

Betulinic acid 2.4 1.8 3-O-succinyl-betulinic acid 1.3 1.3

58


Conclusion

3-O-succinyl-betulinic acid ester can be synthesized from the reaction of betulinic acid with succinic anhydride and its cyototoxic effects on human myeloid leukemia cell and human T4-lymphoblastoid ell is first examined.

m” Planta Med. 61:9-12. . Yasukawa, K., Takido, M., Matsumoto, T., Takeuchi, M . and Nakagawa, S. (1991) “Sterol and

c ACKNOWLEDGEMENT This project was financed by Universiti Teknologi Mara.

REFERENCES 1. Kim, D. S. H. L., Pezzuto, J. M. and Pisha, E.(1998) “ Synthesis of Betulinic Acid Derivatives

with Activity Against Human Melanoma” Bioorg. & Medic.l Chem. Lett. 8:1707-1712. 2. Recio, M. D. C., Giner, R, M., Manez, S., Gueho, J., Julien, H. R., Hostettmann, K. and Rios, J.

L. (1995) “ Investigations on the Steroidal Anti-Inflammatory Activity of Triterpenoids from Diospyros leuco

3Triterpene Derivatives from Plants Inhibit the Effect of a Tumor Promoter and Sitosterol and Betulinic Acid Inhibit Tumor formation in Mouse Skin Twi-Stage Carcingenesis”Oncology 48: 72-76.

4. Hashimoto, F., Kashiwada, Y., Cosentino, L. M., Chen, C. H., Garrett, P. E. and Lee, K.H. (1997) “Anti-Aids Agents. Synthesis and Anti-HIV Activity of Betulinic Acid and Dihidrobetulinic Acid Derivatives” Bioorg. & Medic.l Chem. Lett. 5:2133-2143.

5. Kashiwada, Y., Hashimoto, F., Cosentino, L. M., Chen, C. H., Garrett, P. E. and Lee, K. H. (1996) “ Betulinic Acid and Dihydrobetulinic Acid Derivatives as Potent Anti-HIV Agents” J. Medicinal Chem. 39:1016-1017.

6. Ahmad, F. H., Omar, J. H. and Ali, A. M. (1999) “ Chemical Examination of Local Plant : triterpenes from Leave of Malaysian Callistemon Speciosus D.E.” Ultra Science 11:357-360.

59


KEKABU SEED OIL EXTRACTION AND PUFA ISOLATION

Khairul Asmak Abd. Kadir, Jumat Salimon*

Oleochemistry Programme, School of Chemistry and Food Technology, Faculty of Science

and Technolo r, Malaysia. e-mail : [email protected]

gy, Universiti Kebangsaan Malaysia, 43600 Bangi, Selango*

Abstract: Oil from ke xtr g n-hexane in orbital shaker for 3 hours at 60 The seed oil was obtained by ation ary evaporator. ns were s chromatography (GC). The ids fo kabu seed oil (K (C18:2n6), pa d oleic (C18:1n9) which accou The othe ds includ te (C18:3n6), 3) and lignoceric (C24:0). Af is pr fatty acid using urea co od. The saturated (SFA) and mono acid atty acid (PUFA). The r tio of fatty acid to urea at 1:4, (w/w) was found to be suitable for linoleic acid enrichment in the non-urea fraction, yielding up to 82.9 % linoleic acid Abstrak: Minyak biji k sana dengan init selama 60 oC. Minyak diperolehi ng elarut menggu lingan berp enggunakan gas kromatograf jukk emak major ( yak biji kek da asid linoleik (C18:2n6), a (C18:1n9) ma terdiri darip gamma linolenat (C18:3n6), linolenat (C18:3n3) dan lignoserik ( 4:0). S lisis minyak lemak dipisahkan menggunakan k engkompleksian urea. sid lem ripada asid lemak politaktepu. sbah asid lema ng pali ngkayaan asid fraksi bukan-urea adalah pada isbah 1:4, (b/b) ya silkan 82.9 % Katakunci: Asid lemak politakt , asid linoleik n urea, Ceiba

kabu seed was solvent evapor

e acted usinusing rot

oC at 150 rpm. analysed using ga Fatty acids compositio

major fatty ac und in ke SO) are linoleic lmitic (C16:0) annts 95 %. r remaining aci e gamma linolena linolenate (C18:3n

ter the hydrolysenoic fatty

ocess, the free (MUFA) were separated from p

s were separatedunsaturated f

mplexation methas oly

.

kekabu diekstradengan menyuli

dalam hekkeluar p

150 putaran per mnakan alat penyu

3 jam pada suhu utar. Analisa m

i (GC) menun an asid l 95 %) dalam min abu terdiri daripapalmitik (C16:0) nd oleik nakala selebihnya ada asid lemak

C2 elepas proses hidroak tepu

kekabu, asid-asid kan daaedah p A

ya dan monotaktepu dapat dipisah

Ni n

k kepada ureang mengha

ng sesuai bagi peasid linoleik.

linoleik dalam

epu (PUFA) , pengkompleksia pentandra

Introduction Structured lipid (SL the mid position with medium- e gained considerable

tention recently as nutritional and health supplements [1]. The beneficial health effects of the PUFA re well established. Therefore, synthesizing SL containing PUFA located at the mid position with CFA at the end positions has been the interest of many researchers.

as a precursor of cell membrane arachidonic acid (AA) which in turn is a substrate r the hormone-like substances namely eicosanoid (prostaglandin, thromboxanes and leukotrienes).

nces play important roles in physiological functions of modulating immune and

Figure 1: Linoleic Acid (C18:2n-6)

) possessing long-chain polyunsaturated fatty acids (PUFA) located at chain fatty acids (MCFA) at the end positions hav

ataM Linoleic acid (Figure 1) is one of the two parent essential fatty acids (EFA). EFA are long chain polyunsaturated fatty acid (PUFA) that vital for normal cellular function. The term ‘essential’ implies that they must be supplied in the diet because they are required by the human body but cannot be endogenously synthesized [2]. The functions of linoleic acid (LN) include the role in cell growth, skin and hair condition, reproduction and wound healing. These effects occur largely through the actions of LN in cell membranes [3]. LN also reduces plasma cholesterol levels and reduces platelet aggregation. In the presence ∆6-desaturase enzyme, γ-linolenic acid (GLA) is biosynthesized from LN. GLA servesfoThese substainflammatory responses and are effective for treating atopic eczema and rheumatoid arthritis [4].

COOH

60


Kekabu tree or Ceiba pentandra belong to the family of Bombacaceae. The tree is known by any local vernacular name. For instance, kapok or kabu kabu (Java), Nun (Thai), silk-cotton (West

shaped fruits. They are green at first, ripening to a dull, blackish-brown which split at maturity, releasing seeds covered with silky hairs/lint (Figure 2). Kekabu seed has traditionally been consumed

anmar, Th ia. The unripe seeds were eaten e matured one were fried first. In most W crushed and added oup.

Ri a); un pe fru m ers

It had been documented that , cottonseed oil [9]. In particular to 25 % oil yield. Preliminary study

kekabu see st dominant fatty acid (40-50 ). Therefore, KSO can be seen as a potential local inexpensive source of linoleic acid. Hence,

olation and purification process of linoleic acid from the kekabu seed oil is

methods for PUFA enrichment. It allows the andling of large quantities of material in simple equipment, inexpensive solvents, milder condition,

and versatile process. Its fractional characteristics can be altered simply by changing the amounts of either solvent or urea ratio [10]. This method is also favored by many researchers

nce of ltiple double bonds rather than pure ity [11].

ong-ids

(MC ns whilst this particular paper reports linoleic acid (LN) enrichment from

Materials: Fatty acid standards were obtained from Sigma. Chemicals and solvents were obtained

xane

wer C. The solvent was then evaporated at

Fat

equipped with capillary column BPX 70 (30m x 0.25mm x 0.25µm). The column temperature was

mAfrica) and ceyba or ceiba (Latin Amerika) [5-8]. It fruits from its fifth year, producing cocoa-like

in Asian countries such as Indonesia, Mywhilst t

ailand and Malaysest African countries, the seh

roasted ored were

in s a

cd

a

b

Figure 2:(d)

pened fruit ( ri it (b); seeds embedded in asses of fib (c) and kekabu seed

kekabu seed oil (KSO) was comparable to a well-known oil crop, kekabu seed contains up

conducted reveals that %

d oil consist of linoleic acid as the mo

separation and the isimportant due to it can be easily obtained from natural sources rather than by chemical synthesis. Urea complexation is one of the most appropriate hcost effective

because complexation depends upon the configuration of the fatty acid moieties due to the presemu physical properties such as melting point or solubil This work is a part of ongoing research project on synthesizing structured lipid possessing lchain polyunsaturated fatty acids (PUFA) located at the mid position with medium-chain fatty ac

FA) at the end positiokekabu seed oil by urea inclusion as the sources of PUFA for the production of structured lipid. Experimental Procedures

from Merck and Fisher. The solvents were used without any further purification process. Oil extraction: The oil content in kekabu seeds was determined using the standard proceduredescribed in IUPAC Standard Method [12] with slight modifications. The crushed seeds and he

e put in an orbital shaker at 155 rpm for three hours at 60 o

60 oC by rotary evaporator. The extracted oil was then placed in a vacuum oven and kept at 60 oC for 30 minutes. The oil percentage yield was calculated. The obtained oil was then placed in a darkcontainer and stored in a refrigerator at 0 oC.

ty acid analyses The fatty acids compositions were determined using gas chromatography, Shimadzu GC-17A FID

61


programmed at 120 oC with 3 oC increasing for 57 minutes. The injector and detector temperature w flow rate. The identification of the pea es with the

thentic standards that were analyzed under the same conditions.

Free fatty acid preparation . [13] was employed with a few modifications. 25 hydroxytoluene (BHT) and saponif 95% (v/v) ethanol (66 ml) and water (11 xture was diluted

ith cold water ( th 2 x 100 ml of

rated. Fatty acids from the crystal or UCF were similarly recovered. The

of free fatty acid (FFA): Acids (0.1 g) were treated with 1 ml 0.4 M methanolic (H2SO4) in 10 ml test tube with screw-capped. The test tube was then placed in a water

o

ere set at 260 oC and 280 oC respectively. Nitrogen gas was used as the carrier gas with 0.3 ml/minks was achieved by comparing the retention tim

au

: The procedures reported by Wanasundara et alg o butylated

ied by refluxing with potassium hydroxide solution [(5.75 g in f the kekabu seed oil was treated with 200 ppm

ml)] for 1 hour in a nitroge atmosphere. The saponified mi50 ml) and the unsaponifiable matter was extracted thoroughly wi

n whexane and discarded. The aqueous layer was then acidified to pH=1.0 with hydrochloric acid (3N) and the liberated fatty acids (FFA) were subsequently extracted with 2 x 25 ml hexane. The hexane extract was dried over anhydrous sodium sulphate and the remaining solvent was evaporated to dryness by using a rotary evaporator. The recovered free fatty acids were stored at -5 oC prior to further analyses. Urea complexation: The free fatty acids (FFA) obtained from the saponification process were subsequently undergoing urea complexation according to method proposed by Hidarjat et al. [14] with a slight modifications. The FFA was mixed with hexane and was heated with constant stirring until a clear solution produced. The solution was then cooled and crystallized at 4 oC for 24 hours. After 24 hours, the urea complex fraction (UCF) was separated from the liquid fraction of non-urea complex fraction (NUCF) using a Buchner funnel suction and pressed well to remove mother liquor before and washed with cold solvent saturated with urea. The NUCF was diluted with equal amount of water and subsequently acidified with HCI (6N) to pH 4-5. An equal volume of hexane was added and the mixture was stirred for 1 hour. The hexane layer, containing the liberated fatty acids was separated from the aqueous layer. The hexane layer was then dried over anhydrous sodium sulphate and the solvent was evapopercentage recovery from each fraction was calculated.

Esterification sulphuric acid bath at 70 C for 10 minutes. 0.5 ml of distilled water and 1.0 ml hexane was added. The mixture was centrifuged at 500 rpm. The upper layer, which contained fatty acid methyl ester (FAME) was directly injected to GC for fatty acids analyses. Results and Discussion Fatty acid composition The fatty acid composition of kekabu seed oil (KSO) and their free fatty acids (FFA) after saponification process are shown in Table 1. KSO consists mainly palmitic, stearic, oleic and linoleic whilst the minor fatty acids include γ-linolenic, α-linolenic, myristic, arachidic, behenic and lignoceric. From the ten fatty acids analyzed, 42.73 % is represented by PUFAs (linoleic acid, ALA and GLA), 21.72 % of monounsaturated fatty acids, MUFA (oleic acid), and 35.22 % is saturated fatty acids, SaFA (myristic, palmitic, stearic, arachidic, behenic and lignoceric acids). After the saponification process, the content of free fatty acids was slightly increased. Meanwhile, a considerably decreased in stearic acid content could be due to difficulty during the handling process. This is because stearic acid is in a solid state at room temperature. Urea complexation Theoretically, urea (NH2.CO.NH2) normally crystallizes in tetragonal form with channel of 5.67 Å diameter. However, in the presence of long straight-chain molecules it crystallizes in a hexagonal structure with channels of 8-12 Å diameter within the hexagonal crystals [15]. The channels formed are sufficiently large to accommodate aliphatic chains. Straight-chain saturated fatty acids with six carbon atoms or more are readily adducted. The presence of double bonds in the carbon chain increases the bulk of the molecule and reduces the probability of its complexation with urea.

62


Monoenes are more readily complexed as compared to dienes which, in turn, are more readily complexed than trienes. The saturated fatty acids, monoenes and, to a lesser extent, dienes are

y

Table 1: Fatty acid composition of kekabu seed oil (KSO)

Composition* (%)

cr stallized with urea (UCF) and non-urea complex fraction (NUCF) in the solution is separated by filtration [11].

Fatty Acids B A

Major acids Palmitic Stearic

C16:0 C18:0

22.58 ± 0.00

24.35 ± 0.25

Oleic Linoleic

C18:1(ω-9) C18:2(ω-6)

11.83 ± 0.34 3.643 ± 0.13 23.57 ± 0.11 40.51 ± 0.06

88

Minor acids γ-linolenic α-linolenic

C18:3(ω-6) C18:3(ω-3)

2.159 ± 0.14 0.5690

1.948 ± 0.11

21.72 ± 0.20 39.99 ± 0.19

Myristic Arachidic Behenic Lignoceric Others

C 14:0 C 20:0 C 22:0 C 24:0

± 0.03 0.0800 ±0.01 0.1290 ± 0.02 0.4680 ± 0.02 0.1335 ± 0.01 0.0392 ± 0.01

0.7170 ± 0.09 0 ± 0.00

0.5850 ± 0.09 0.5515 ± 0.21 3.015 ± 0.13 1.139 ± 0.

35.22 ± 0.04 21.72 ± 0.20 42.72 ± 0.29

32.14 ± 0.35 23.57 ± 0.21 43.18 ± 0.20

Σ SFA1

Σ UFA2

Σ PUFA3

* Values were means of duplicate samples ± standard deviation; A - Kekabu seed oil (KSO); B - Free fatty acid of KSO after saponification. 1 Saturated fatty acid (myristic, palmitic, stearic, arachidic, behenic & lignoceric) 2 Unsaturated fatty acid (oleic) 3 Polyunsaturated fatty acid (linoleic, α-linolenic & α -linolenic)

Table 2 showed the major fatty acid composition of kekabu seed oil free fatty acids (KSO-FFA) after urea complexation. Due to the presence of two double bond, linoleic acid is crystallized with urea in a lesser extent compared to palmitic (C16:0). stearic (C18:0) dan oleic (C18:1) acids. The enrichment of linoleic acid in the non-urea complex fraction (NUCF) increased in parallel with the increasing amount of urea until ratio of 1:4 (FFA:urea, w/w). At the ratio of 1:5, the percentage of linoleic acid obtained was decreased. This could be as a result of the larger extent of linoleic acid that complexed with urea as the amount of urea increased. The enrichment of linoleic acid performed the best at the ratio of 1:4 (FFA:urea, w/w) with up to 82 % with a totally removal of palmitic and oleic acid. Conclusion PUFA enrichment in kekabu seed oil was done with the most favorable result at the ratio free fatty acids to urea 1:4. At this ratio, linoleic acid was concentrated up to two fold, from 40 % in the FFA to 82.9 % in the non-urea fraction.

63


the National Science

l. Studies, Uni.Calif. 9: 185-216

.

Table 2: Fatty acid composition of saponified kekabu seed oil (KSO) after urea complexation process

Compositiona (%) The Ratio of Fatty acid to Urea

Major tty Acid

FFAFa

b Fractionsc 1:1 1:2 1:3 1:4 1:5 24.35 ± 0.25 1 46.75 ± 0.15 47.93 ± 1.07 34.33 ± 0.78 30.18 ± 0.72 28.45 ± 0.73 P

( 0.00 almitic C16:0)

2 5.34 ± 0.08 0.41 ± 0.71 0 ± 0.00 0 ± 0.00 0 ±

3.643 ± 0.13

1 5.79 ± 0.11 4.25 ± 0.08 3.08 ± 0.15 3.69 ± 0.59 1.12 ± 0.16 Stearic C18:0)

(

2 0.54 ± 0.41 0.94 ± 0.04 1.66 ± 0.05 2.77 ± 0.29 0 ± 0.000

23.57 ±

0.11 1 20.05 ± 0.01 32.34 ± 0.62 32.19 ± 0.78 28.51 ± 0.97 27.98 ± 0.77 Oleic 18:1) (

.07 C

2 26.41 ± 0.41 11.66 ± 0.42 0 ± 0.00 0 ± 0.00 0.48 ± 0

40.51 ± 0.06

1 22.69 ± 0.15 13.05 ± 0.30 26.57 ± 1.13 33.04 ± 0.87 36.03 ± 0.06 L(C

.45 a Values were means of duplicate samples ± standard deviation; b Free fatty acid of KSO after saponification. c 1 = Crystal fraction / Urea complex fraction (UCF); 2 = Liquid fraction / Non-urea complex fraction (NUCF) Temperature = 4 oC; Time course = 24 hours

Acknowledgements We would like to thank Universiti Kebangsaan Malaysia and the Ministry of Science and Technology & Innovation (MOSTI) for research grant # 09-02-02-0115 EA 277 and

ellowship fund for Miss Khairul Asmak Abdul Kadir

inoleic 18:2n-6)

2 56.52 ± 1.87 71.32 ± 1.54 80.53 ± 0.43 82.91 ± 0.09 77.05 ± 2

F References

1. Halldorsson, A., Magnusson, C.D. & Haraldsson, G. (2001) “Chemoenzymatic Synthesis of Structured TAG” Tetrahedron Letters. 42: 7675-7677.

2. Gunstone, F.D. & Herslof, B.G. (2000) “Lipid Glossary 2”, England: PJ Barnes & Associates 3. Smit, E.N., Muskiet, F.A.J. & Boersma, E.R. (2004) “The Possible Role of Essential Fatty Acids in the

Pathophysiology of Malnutrition: a review” Prostaglandins, Leukotrienes and Essential FattyAcids. 71: 241-250. 4. Berry, E.M. (2001) “Are Diets High in Omega-6 Polyunsaturated Fatty Acids Unhealthy? European Heart Journal

Supplements. 3: D37-D41 5. H.G. Baker. (1965) “The Evolution of The Cultivated Kapok Tree” Res. Ser. Inst. Intn

6. A.C. Zeven. (1979) “Kapok; Ceiba pentandra (Bombacaceae) in N. W. Simmonds (Ed.) Evolution of crop plants”, USA: Longman Inc.

7. Allen, B.M. (1971) “Some Common Trees of Malaysia and Singapore”, Singapore: Singapore Offset Printing (Pte.) Ltd

8. Fong, C.H. & Enoch., I.C. (1988) “Malaysian Trees in Colour”, Kuala Lumpur: Tropical Press Sdn. Bhd. 9. J.G.Vaughan. (1970) “The Stucture and Utilization of Oil Seeds”, Great Britain: The Chaucer Press. 10. Guil-Guerrero, J.L. & Belarbi, E.H. (2001) “Purification Process for Cod Liver Oil Polyunsaturated Fatty Acids” J.

Am. Oil. Chem. Soc. 78(54): 477-482 11 Shahidi, F & Wanasundara, U.N. (1998) “Omega-3 Fatty Acid Concentrates: Nutritional Aspect and Production

Technologies” Trends in Food Sciene and Technology. 9: 230-240. 12. International Union of Pure and Applied Chemistry. (1979) “Standard Methods for the Analysis of Oils, Fats and

Derivatives. (6th ed)”, Great Britain: Pergamon Press. 13. Wanasundara, U.N & Shahidi, F. (1999) “Concentration of Omega-3-Polyunsaturated Fatty Acids of Seal Slubber Oil

by Urea Complexations: Optimization of Reaction Conditions” Food Chemistry. 65: 41-49 14. Hidarjat, K., Ching, C.B., Rao, M.S. (1995) “Preparative-scale Liquid Chromatography of ω-3 Fatty Acids from Fish

Oil Sources. Journal of Chromatography A. 702: 215-221 15. Gunstone, F.D & Frank, A.N. (1983) “Lipids in Food Chemistry, Biochemistry and Technology”, Oxford: Pergamon

Press.

64


TOXICITY AND ANTITERMITE ACTIVITIES OF THE ESSENTIAL OILS FROM PIPER

SARMENTOSUM

Faculty of Resource Science and Technology

e: 082 679179; Fax: 0 [email protected] Abstract. T er sarmentos re hydrodis o Clevenger-type apparatus, a eld of essential oil of 1.10% (v eight) was o d. The leaf oils were analyz nd GC-MS. A to 1 componen e identified. lenol (21.0%), myristicin ( 18. d (E,E)-farnesol (10.5%) were the major compounds found in the leaf oil. The leaf oil showed ory activity against the larvae o mia salina with LC50 value mL, and 100% m y within tw at 1% concentration against the subterranea termes sp.). The crude extract hen subjected to bioassay-guided isolation using silica gel column chromatography, and eluted with hexane containing increasing volumes of e and yielded three pure compounds. oxicity and a ite activities of the three c ere determined. und 2 show most potent activity against the larvae of A 50 value of g/mL, while the LC50 v mpound 3 and compound g/mL and 22. L respectiv ompound 3 showed the strongest inhibitory a nst the subterrane ite (Coptot sp.) with 10 ortality after 3 days at 0. n followed pound 2 with the same mo rate at 0.5% concentratio showed the weakest inhibitory a with 80% m after 3 days at 2% concent Key words: mentosum; essential oil; bioassay-guid ation; toxici termite activity Introductio The genus to the family ceae, comprising more than 700 species distributed throughout and subtropical regions of the world ost of the species in this genus are aromatic, w ial climbers and shrub. Th r species have high commercial, economical portance. Many species have been shown to possess antimicrobial, antifungal, nt, insecticidal, allelopathic and antitum [1]. us compounds, including a ropenylphe , neolignans, terpenes, steroids, kawapyrones, chalcones, flavones and flavanones have been isolated from different Piper of Piper specie viewed by severa s [2, 3]

Piper s Roxb., locally k as “kaduk” creeping her erect, slender branchlets mm ound in dam s, ri ks cleared and cultivated lands in Sarawak [4]. The leaves are used in folk medicine as counter-irritants in poultices for headaches and pains in bones. A decoction of the boile may be utilized to treat coughs, influenza, toothaches and rheumatism. Th is also a rem r toothache be made into a wash for mititis on the fee bioactive und, isoasar s been isolated from the r mentosum and showed insecticidal property similar to DDT [6]. Four phenylprop from the benz luble fractio e met extract showed nti l extract of

the a t nerve-hem ia the plant showed considerable antimalarial activity against Plasmodium falciparum and Plasmodium berghei parasites [9], while the water extract of the whole plant had a hypoglycaemic effect in rats [10]. In addition, some amides isolated from the hexane and methanol extracts of fruits exhibited antituberculosis and antiplasmodial activities [11]. A resent study showed that this plant is a good source of natural antioxidants as the

Chieng T.C.*, Assim Z.B., and Fasihuddin B.A.

Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak

* Phon 82 672275; ch s.my

he leaves of Pipnd an average yi

um we tilled using the m/dry w

dified btaine

ed by GC a tal of 3 ts wer Spathu18.8%), β-caryophyllene ( 2%) an

inhibit f Arteof 35.2 µg/ ortalit o days

n termite (Copto was t

ethyl acetatompounds w

Their t ntitermCompo ed the

. salina with LC 7.5 µ alues for co1 were 17.2 µ 5 µg/m ely. Cctivity agai an term ermes 0% m

1% concentratio 1

by com rtalityn. Compound

ration. ctivity ortality

Piper sar ed isol ty; anti

n

Piper belongs Piperathe tropical [1]. Moody perenn rarely e Pipe

and medicinal imantioxida our activities Variolkaloids/amides, p nols, lignans

species. The chemistrys has been re l researcher .

armentosum nown , is a b withabout 30 cm tall. It is co only f p open space verban

d leaves e root t [5]. A

edy focompo

and mayone hafungoid der

oots of P. saranoids isolated ene-so n of th hanolic leaf

microbial activity against Escherichia coli and Bacillus subtilis [7], and the methano blocking activity in ra

aleaves w s found to possess a profound neuromuscularid phragm preparation [8]. The chloroform extract of

65


methanol extracts were found to possess high antioxidant activity, which may be attributed to the high contents of vitamin E and xanthophylls [12]. This paper reported three compou olated oassay ed ch graphic separation from the essentia xtracte the l of P. ntosum bioac of these compou e sh arvae bterra termite e also d.

Plant materials

The leave samples of Piper sarmentosum was collected around Kuching area. Sample was identified and authenticated by a plant taxonomist. Voucher specimens was deposited at the Herbarium of Universiti Malaysia Sarawak.

Extraction and analysis

The randomly picked leaves were air dried and ground. About 100 g of the ground samples were hydrodistilled using the modified Clevenger-type apparatus for 6 hours, and the oily layers obtained were separated and dried over anhydrous sodium sulphate and stored in vial at 4 – 5oC. The yield was calculated based on dry weight of the plant material. The oils were analyzed on a Shimadzu GC-17A chromatograph equipped with a flame ionization detector using fused silica capillary column DB-5 (25 m × 0.22 mm ID and film thickness 0.25µm). The operation parameters were: N as carrier gas at flow rate of 20 cm3 min−1, splitless, injector temperature 2 ally at 50oC for 2 minutes, and ramped to 300oC at a rate of 6.5 min−1 and held for 7 minutes. The oils were also analyzed using GC-MS (S imadz GC-17A) fixed with the same type of capillary colu were: He as carrier gas at flow rate of 20 cm3 min−1, splitless, injector temperature 250oC, and detector temperature 280oC. The column was programmed initially at 50oC for 2 minutes, and then ramped to 300oC at a rate of 6.5oC min−1 and held for 7 minutes. The components were identified tentatively by comparing their Kovat’s retention indices with literature values and their mass spectral data with those from NIST mass spectral database. The retention indices were calculated for all components using a homologous series of n-alkanes as standards [13]. For mass spectral analysis, the components were identified by matching the MS with those of authentic standards held in the NIST library. Only similarity indices of 85 or higher were taken as proof of identity [14]. Bioassay-guided fractionation The biological activity of the extract was performed against brine shrimp larvae (A. salina) and termites (Coptotermes sp.) using the methods described below. About 2.0 mL of the a

each) were mbined into 6 groups (PS1 to PS6) based on the similarities in TLC profiles. The

st larvae of A. salina was found in fractions PS1, PS4 and PS6. These 3 fractions were en submitted to further fractionation and purification. Fraction PS1 (352 mg) was subjected to CC

with a mixture of exane:benzene:chloroform (3:1:2) yielding 15 fractions, which were pooled into 3 groups.

group 2 [hexane:benzene:chloroform (3:1:2)] yielded 157 mg of compound (2). raction PS6 (272 mg) was subjected to CC on silica gel and eluted with gradient mixture of

OAc (4:1)] yielded 136 mg of compound (3). The bioactivities of these three mpounds were determined against larvae of A.salina and termites (Coptotermes sp.)

nds isd from

by means of bieaves

-guid. The

romatotivityl oil e sarme

nds against brin rimp l and su nean s wer studie Materials and Methods

280oC, and detector temperature 320oC. The column was programmed initi

oCh u

mn as GC and under ionization energy of 70 eV. The operation parameters

essential oil was applied to a silica gel column, and eluted with hexane and ure of hexane:EtOAc (19:1, 9:1, 4:1, 1:1). A total of 70 fractions (25 mLgradient mixt

collected and coactivity againthon silica gel and eluted with gradient mixture of hexane:EtOAc (9:1, 4:1) yielding 30 fractions, which were pooled into 3 groups. Preparative TLC of group 1[hexane:EtOAc (9:1)] yielded 252 mg of compound (1). Fraction PS4 (212 mg) was subjected to CC on silica gel and elutedhPreparative TLC of Fhexane:EtOAc (4:1, 1:1) yielding 15 fractions, which were pooled into 3 groups. Preparative TLC of group 2 [hexane:Etco

66


Toxicity assay

The p arvae of

er

well m nu

ned as the bility. Contr run simultaneously. All experiments were run in

Antit

ma Copplaste

m

te

was aworke the initiation of

iwere each d ach treatment was performed 6 times (3 wells/multidish × 2 times).

Resul

rooil. T1). Se squiterpene hydrocarbons representing 30.3%

hydrofarnes main oxygenated sesquiterpenes. Monoterpenoids only made up of 5.1% of

T .2 µg/mL he subterranean termite

iwith a

pi

of A. ivity against the larvae of A. salina with LC50 value of 7.5 µg/mL, while the LC50 values for compound 3 and compound 1 were 17.2 µg/mL and 22.5 µg/mL respectively. Compound 3 possess the strongest inhibitory activity against the subterranean termite with 100% mortality after 3 days at 0.1% concentration (Figure 1) followed by compound 2 with the similar mortality rate at 0.5%

rotocol established by Mclaughlin [15] was adopted for the toxicity assay against the l

A. salina. The test samples were prepared by dissolving separately 2 mg of each extract in 2 mL of methanol. From these solutions, 500, 50, and 5 µL were transferred to vials. The solvent was removed und vacuum and 5 mL of artificial seawater was added to each vial, resulting in final concentrations of 100, 10 and 1 µg mL−1 respectively. Then 2 mL of these diluted solutions were transferred to 24

ultidish and second instar larvae of A. salina (10 per well) were added. After 24 hours contact, mber of dead larvae in each well wathe s counted and the percentage of death was plotted against

the concentrations (on a log scale). The LC50 values were determined graphically. The LC50 is defi lethal concentration of the sample at which 50% of the larvae do not show visible mools with and without thymol (10 µg mL−1) were

triplicate.

ermite assay The odified method established by Sakasegawa et al [16] was used for the antitermite assay against

totermes sp. collected around Kuching area. The termites were cultured for 2 – 3 days in a r container at room temperature. In the bioassay for termiticidal activity, cut filter paper

(dia eter 35 mm) were placed in each well of a 6-well multidish (3 rows × 2 lines, hole diameter 35 mm). The samples were diluted to 10.0%, 1.0% and 0.1% with methanol. Exactly 80 µL of these

d samples were pipetted onto the filter paper in each well of one line. Exactly 80 µL of methadilu nol were placed on the filter paper in each well of the other line, which acted as control. The methanol

llowed to evaporate from the filter paper for several hours. 6 termites (5 undifferentiated rs and a soldier) were placed on each well. The absence of soldier causes

phys ological process in which a certain number of workers become soldiers [17]. The multidishes closed tightly and kept at 25oC in an incubator. The numbers of living termites were counted ay. E

ts and Discussion Hyd distillation of the air dried leaves of P. sarmentosum yielded 1.10% (v/dry weight) of essential

here were 31 components (greater than 0.1%) identified in the leaf oil of P. sarmentosum (Table squiterpenoids were the main constituents with se

and oxygenated sesquiterpenes 61.0% of the oil. The major component of the sesquiterpenes carbons was β-caryophyllene (18.2%) while spathulenol (21.0%), myristicin (18.8%) and (E,E)-ol (10.5%) were the

the oils with α-phellandrene the only monoterpene hydrocarbon present. his leaf oil showed inhibitory activity against the larvae of A. salina with LC50 value of 35

, and 100% mortality within two days at 1% concentration against t(Coptotermes sp.). After first fractionation, the fractions obtained were subjected to biological activ ty. The biological activity against larvae of A. salina was found in fractions PS1, PS4 and PS6

ll showing LC50 value of less than 30 µg/mL after 24 hours of contact (Table 2). The result showed that the three fractions might contain bioactive components. Bioassay-guided chromatographic separation of the three active fractions afforded three

ounds. All the three compounds were subsequently tested againscom t A. salina and subterranean term te (Coptotermes sp.). Compound 2 and 3 showed stronger biological activity against the larvae

salina and termites compared to compound 1. Compound 2 showed the most potent act

67


concentration (F 80% mortality after 3 days hip should be furthe As th ermites,

e data obtained will be used for further study to develop environmental friendly termiticital compo

Tabl um

igure 2). Compound 1 showed the weakest inhibitory activity with at 2% concentration (Figure 3). However, detailed structure-activity relations

r investigated. ere is no previous report on the activity of these three volatile oil components on t

thunds.

e 1: Chemical composition of the essential oils from the leaves of P. sarmentos

Kovat’s Index Compound 1 2

% RA KI KI

α-Phellandrene 0.78 1005 1007 Piperitone 1245 1245 0.67 Cinnamyl alcohol 1314 1312 0.18

1499 1500 0.21 Elemicin 1512 1514 0.88

0.21 β-Eudesmol 1648 1648 0.58

674 0.29 adinol 1677 1676 0.70

E,Z-Farnesol 1696 1696 2.19

Eugenol 1366 1364 1.80 α-Copaene 1377 1377 0.29 Methyl eugenol 1407 1407 1.63 α-Ionone 1422 1422 2.96 γ-Elemene 1426 1425 2.48 β-Caryophyllene 1465 1467 18.19 α-Humulene 1469 1467 0.86 β-Guaiene 1481 1483 0.43 Germacrene D 1488 1487 1.26 Ethyl laurate 1494 1494 1.09 α-Farnesene

Bicylogermacrene 1516 1517 0.34 δ-Cadinene 1519 1519 0.72 Cadinadiene 1526 1527 0.96 Myristicin 1533 1532 18.77 γ-Cadinene 1543 1543 2.26 Germacrene B 1562 1562 2.26 Guaiol 1587 1589 0.69 Dehydrocarveol 1591 1593 0.85 Spathulenol 1617 1619 20.98 T-Muurolol 1636 1635

β-Bisabolol 1668 1666 0.26 δ-Cadinol 1673 1α-C

E,E-Farnesol 1720 1722 10.50

KI1 = Kovat’s retention indices obtained on a DB-5 column using the series of n-alkanes. KI2 = Kovat’s retention indices from literature. [13] RA = Relative area (peak area relative to total peak area).

68


Table 2: LC50 values against larvae of A.salina.

Fraction PS1 PS2 PS3 PS4 PS5 PS6 LC50 (µg/mL) 29.1 >100 nd* 21.6 82.0 23.5

nd* – not done due to inadequate amount of sample

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

% D

eath

2.00%1.00%0.50%0.10%Control

1 2 3 4

Day

Figure 1: Antitermite activity of Compound (1) at different concentrations

0

20

40

1 2 3 4

Day

60

80

100

120

% D

eath

2.00%

1.00%

0.50%

0.10%

Control


120

40

80

100

0

20

1 2 3 4Day

2.00%

1.00%

0.50%

0.10%

60

% D

eath

Control


69


Conclu

cknowledgement

his research was financially supported by a fundamental grant 01/19/295/2002(33) from Universiti

oil Piper species. Flavour Fragrance. J., 14, 279 - 282.

2. S

common wild Piper of Sarawak. In: Ibrahim, M.Y., Bong, C.E.J. & Ipor, I.B. (Eds). The Pepper Industry: Problems and Prospect. Universiti Pertanian Malaysia, Bintulu Campus, 72 – 78.

. Muhammad, Z. & Mustafa, A.M., (1994). Traditional Malay Medicinal Plants. Fajar Bakti,

Kuala Lumpur.

6. Satariah, H., Hapipah, M.A., Khalijah, A., Abdul Aziz, K., Habsah, A.K., Kamaliah, M. & Hadi, A.H., (1999). Chemical constituents and insecticidal activity of Piper sarmentosum. In: Manaf Ali, A., Khozirah, S & Zuriati, Z. (Eds.), Phytochemical and Biopharmaceutins from the Malaysian Rain Forest. FRIM, Kepong, 62-66.

7. Masuda, T., Inamuzi, A., Yamada, Y., Padolina, W.G., Kikuzaki, H. & Nakatani, N., (1991). Antimicrobial phenylpropanoids from Piper sarmentosum. Phytochemistry 30, 3227–3228

8. Ridtitid, W., Rattanaprom, W., Thaina, P., Chittrakarn, S., & Sunbhanich, M. (1998). Neuromuscular blocking activity of methanolic extract of Piper sarmentosum leaves in the rat phrenic nerve–hemidiaphragm preparation. J. Ethnopharmacol., 61, 135–142.

9. Najib Nik, A., Rahman, N., Furuta, T., Kojima, S., Takane, K., & Ali Mohd, M., (1999). m tivity of extracts of Malaysian medicinal plants. J. Ethnopharmacol. 64, 249–

. , S. J.

Ethno Rukachaisirikul, T., Siriwattanakit, P., Sukcharoenphol, K., Wongvein, C., Ruttanaweang, P.,

. & Suksamrarn, A. (2004). Chemical constituents and bioactivity of Piper sarmentosum. J. Ethnopharmacol., 93, 173-176.

sion The finding of this study showed that essential oil from leaves of P. samentosum contains larvicidal and termiticidal components. Further studies are required to increase the lethality of these components due to the synergy achieved by the presence of other minor components of the oil. A TMalaysia Sarawak. References

1. Sumathykutty, M.A., Rao, J.M., Padmakumari, K.P., & Narayanan, C.S., 1999. Essential constituents of some

engupta, S., & Ray, A.B., (1987). The chemistry of Piper species: a review. Fitoterapia, 58, 147-165

3. Parmer, V.S., Jain, S.C., Bisht, K.S., Jain, R., Taneja, P., Jha, A., Tyagi, O.D., Prasad, A.K., Wengel, J., Olsen, C.E., & Boll, P.M., 1997. Phytochemistry of the Genus Piper. Phytochemistry, 46 (4), 597 – 673.

4. Tawan, C.S. & Ipor, I.B., (1993). Some

5

Anti alarial ac25 4

10 Peungvicha, P., Thirawarapan, S., Temsiririrkkul, R., Watanabe, H., Prasain, J. K., & Kadota(1998). Hypoglycemic effect of the water extract of Piper sarmentosum in rats.

pharmacol., 60, 27–32. 11.

Wongwattanavuch, P

12. Chanwitheesuk, A., Teerawutgulrag, A. & Rakariyatham, N. (2005). Screening of antioxidant activity and antioxidant compounds of some edible plants of Thailand. Food Chemistry, 92, 491-497.

13. Acree, T. and Arn, H. (2004). http://www.Flavornet.com. [online], retrieved on 7 March, 2005. 14. Adam, R.P., 1995. Identification of Essential Oil Components by Gas Chromatography/Mass

Spectrometry. Allured, Carol Stream, IL., USA.

70


15. McLaughlin, J.L., (1991). Grown gall tumours on potato disc and brine shrimp lethality: two simple bioassay for higher plants screening and fractionation. In: Hostettmann, K. (Ed), Assays for Bioactivity, Academic Press, San Diego, 2-32.

16. Sakasegawa, M., Hori, K. & Yatagai, M., (2003). Composition and antitermite activities of laleuca species. J. Wood Sci., 49, 181-187.

, M., Schrader, K.K., Dayan, F.E. and Osbrink, W., (2002). Lepidium meyenii Walp.. Phytochemistry, 61, 149-155.

essential oils from Me7. Tellez, M.R., Khan, I.A., Kobaisy1

Composition of the essential oil of

71


MICROBIAL INFLUENCED CORROSION CAPABILITY OF SULFATE-REDUCING BACTERIA ISOLATED FROM MALAYSIAN

OF THE SHIPYARD AND ENGINEERING HARBOURS, PASIR GUDANG

Fathul Karim Sahrani∗, Zaharah Ibrahim∗, Madzlan Aziz ∗∗ and Adibah Yahya∗

∗Department of Biology, Faculty of Science, Universiti Teknologi Malaysia, 81300 Skudai, Johor Darul Takzim

∗∗Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81300 Skudai, Johor Darul Takzim

e-mail: [email protected]

the corrosion product was nfirmed by XRD analysis.

jud dalam produk kakisan melalui analisis XRD. Keywords: Sulfate-reducing bacteria, a al influenced corrosion, corrosion

otential, localized corrosion. Scanning electron microscopy.

Introduc

Sulfate-reducing bacteria (SRB) are usually part of the indigenous community of microorganisms in an ecosystem and are of great utilitarian and academic interest. They are of significant economic sectors and of environmental concern because of their roles in contamination of petroleum products and anaerobic corrosion of steel.

The role of SRB in anaerobic corrosion processes is indisputable [1,2,3,4]. Corrosion processes involve biotic and abiotic factors. The corrosion of stainless steel in marine systems, for

Abstract. Sulfate-reducing bacteria (SRB), implicated in microbiologically influenced corrosion, were isolated from the deep subsurface at Malaysian Shipyard and Engineering (MSE) harbours, Pasir Gudang. Alloy steel specimens were exposed to natural seawater to study the weight loss of biocorrosion in both biotic and abiotic environments. Open circuit potentials (OCP) for the specimens in presence and absence of SRB grown in VMNI media have been performed. Scanning electron microscopy (SEM) images were obtained for the specimens, which were exposed to SRB cultures. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyse the corrosion products. Open circuit potential measured for 15 days showed great differences in the presence and absence of SRB in the VMNI culture media. SEM observations resulted in good correlation with open circuit potential data which show that the experimentally observed strong acceleration in pitting corrosion process , induced by the SRB. EDS analysis of specimens indicated high counts of sulphur and this confirms the presence of sulphur inco

Abstrak. Bakteria penurun sulfat (SRB) yang mempengaruhi kakisan telah dipencilkan daripada dasar persekitaran MSE, Pasir Gudang. Spesimen keluli aloi telah di dedahkan dalam air laut sebenar untuk mendapatkan kehilangan berat oleh proses kakisan bio dalam persekitaran biotik dan abiotik. Keupayaan litar terbuka (OCP) terhadap spesimen dalam medium VMNI dengan dan tanpa kehadiran SRB turut dijalankan. Imej dari spektroskopi imbasan elektron juga diperolehi dari spesimen yang didedahkan kepada kultur SRB. Spektroskopi tenaga penyebaran (EDS) dan penyebaran sinar-x (XRD) digunakan untuk menganalisis produk kakisan. Pemonitoran selama 15 hari bagi keupayaan litar terbuka menujukkan terdapat perbezaan yang besar dengan dan tanpa kehadiran SRB. Hasil pemerhatian daripada SEM menunjukkan terdapat korelasi yang baik bagi menerangkan data keupayaan litar terbuka dimana berlaku peningkatan yang ketara dalam proses kakisan berlubang. Analisis EDS terhadap spesimen menunjukkan kiraan yang tinggi kepada unsur sulfur dan dibuktikan bahawa unsur ini wu

lloy steel, microbiologic lyp

tion

72


example, is influenced by micro organisms and may be entirely biotic. Biocorrosion processes on metal surfaces depend on the physiology of the microbial community developing under the influence of the chemical and physical parameters of the environment. The process of corrosion is directly linked to the growth and activities of these bacteria. Open circuit potentials (OCP) for steel that are exposed to natural seawater are ennobled, which may result in localized corrosion on their surfaces [5,6]. Ennoblement of passive metal does not occur when exposed to sterile seawater [7]. Natural SRBs are a main cause of OCP ennoblement, which be related to the occurrence of localized corrosion. Due to its simplicity, open-circuit corrosion potential measurements have been used in MIC studies for many years [8]. A plot of potential as a function of time could be useful to detect the initiation of an accelerated attack of SRB [9]. Rapid changes in the corrosion potential can be used to indicate depolarization, or enhancement of the anodic reaction, or to the formation of a semi-protective film [10]. On the other hand, the important mechanisms potentially involved in case of MIC can be classified as follows: (i) Cathodic depolarization; (ii) Formation of occluded area on metal surface; (iii) Fixing the anodic sites and (iv) Under deposit acid attack. Cathodic depolarization, also known as the ‘classical theory’ is based on the idea that certain strains of SRB possess the hydrogenase enzyme and therefore are able to catalyse both the reversible reactions involving

and the reduction of sulfate by molecular hydrogen. This paper primarily focuses on the a on cathodic corrosion processes.

ct f these erile seawater has a pical f

de (SCE). Measurement nging ith time is important for estimating the effect of depolarizers on corrosion reactions.

r se of Eoc means depolarization of cathode and corrosion. A drop in potential is evidence for decreased corrosion [17]. The present paper aims at investigating an ennoblement of open circuit potential (OCP) of alloy steel, which is responsible for the occurrence of localized corrosion. Weight loss measurement, scanning electron microscopy (SEM) examinations and electron diffraction spectroscopy (EDS), have been performed on steel samples exposed to filter-sterilized seawater and VMNI media with and without living cultures of the SRB. Experimental

Media and Cultivation Conditions

g owth medium for marine SRB was proposed Zinkevich et al. (1996) which is modification of

Cl2.6H2O (0.04g); MgSO4.7H2O .06g); sodium lactate (6.0ml); yeast extract (1.0g); FeSO .7H O (0.5g); sodium citrate (0.3g);

mins (2.0ml); .1g). All of the chemicals were weighed and then made into

1 litre solution with filter-sterilized seawater. The media was degassed with N2 for 30 minutes to create anaerobic condition and pH was adjusted to 7.2 using 1.0M NaOH before autoclaving at 121oC it was left to cool room temperature before being inoculated with the SRB.

hydrogenimpact of bacteri

Previous work reported the possibility of detecting a cathodic depolarization under the impabacteria [11,12,13]. The cathodic curve obtained on alloy steel in sto

ty orm for the corrosion process with intense depolarization on reaction with hydrogen. It means that the speed of corrosion of the sample was determined by the removal of hydrogen layer on working electrode. The effect of hydrogen removal from the metal surface and ferrous sulphide (FeS) formation in SRB-induced corrosion was recently stressed by Little and Wagner (1997) [14]. The contribution of FeS to the cathodic depolarization was investigated by Tiller and Booth (1962) [15]. The rate of corrosion was proportional to the amount of FeS added and dependent on the contact of FeS with metal surfaces. These results allowed reinterpretation of the way metal corrosion is induced by sulfate reducers.

Electrochemical methods have been used to follow corrosion processes [16]. The Eoc (open circuit potential) is defined as the potential between the metal coupon (working electrode) and the platinum counter electrode relative to the reference saturated calomel electroof Eoc cha wAn inc ea

A r byPosgate’s Marine medium C [18]: KH2PO4 (0.5g); NH4Cl (1.0g); Ca(0 4 2Na2SO4 (4.5g); casamino acids (2.0g); thioglycillic acid (0.1g); trace elements (1.0ml); vita

tryptone (2.0g); ascorbic acids (0a

73


The SRB were left to grow for 3 – 5 days in anaerobic jars at temperatures 35oC. The indication of successful incubation was blackening of the medium within 2-3 days and generation of H2S were recorded as a positive indication for presence of SRB. Colony morphological characteristics including size, shape, colour, margin, configuration and elevation were examined using stereomicroscope (Leica Zoom 2000 Z45V). The 16S rRNA analysis were carried out and work is currently on going. Weight loss study in both biotic and abiotic environment

The composition (% wt) of the low- carbon alloy steels was as follows: C, 0.35; Cr, 1.0; Si, 0.8; Mn,

8 o, 0.25; Ni, 0.25; Fe (remaining %). Test coupons were prepared according to the ASTM an ard fo cyli ds (dim nsion .5 mm mm thickness). Coupons were finished y using 120, 320, 1200 grid SiC paper, th tap water and acetone and

, eig and abiotic conditions. Seawater was collected from e Mal

0. ; Mt ds r ndrical ro e : 9 diameter x 3

600, 800, 1000, washed wibfinally air-dried.

Before immersion into the natural seawater, coupons were left in alcohol for about 24hhed, marked and then exposed to the biotic w

th aysian Shipyard and Engineering harbours, Pasir Gudang. In abiotic conditions, seawater was sterilized by filtering through a 0.45µm membrane before use. During the 6 months period that the coupons were immersed in seawater, coupons were taken out monthly, cleaned, weighed after drying and the corrosion rates, vc, were determined.

(a) (b)

Epoxy polyester

Cuprumwire

Glasstube

Alloy steel Coupons

Fig. 1. (a) Schematic diagram of alloy steel concentric electrode (working electrode) and (b)

Electrochemical cell

Potential change studies

Ecorr changes were measured against a standard saturated Calomel electrode

c in the same compartment (Fig. 1). The exposed electrodes used under various conditions were bedded in polyester had approximate diameter of 9.8 mm. A copper wire was soldered at the rear

ntial of the allo n various solutions: (a) filter-sterilized seawater (control) ; (b)

MNI (control); (c) VMNI+SRB1; (d) VMNI+SRB11 and (e) VMNI+SRB1+SRB11 were measured using a

Saturated calomel electrode

working electrode

Nitrogen gas

Open-circuit potential, pla ed emof the electrode which was housed in a glass tube to protect it from the test medium. The pote

y steel electrode immersed iV

multimeter (model Megger M8013) and was incubated under semi-anaerobic condition for 15 days. For all measurements, samples collected were VMNI filter-sterilized seawater taken from the

74


vicinity of tested sites and passed through a 0.45µm filter membrane. Prior to the experiment, all glass wares were autoclaved and aseptic procedures were followed. To identify the corrosion products, the electrode used in monitoring potential change was analysed using XRD, SEM observations and EDS.

Corrosion rate = (K x W) / (A x T x D) Where:

K = constant (8.76 x 104), T = time of exposure in hours, A = area in cm2, W = mass loss in grams, and D = density in g/cm3

Results and Discussion Weight Loss Study The weight loss and corrosion rate of alloy steel with time under biotic and abiotic environment is shown in Fig. 4(a) and 4(b). The overall corrosion rate was calculated from the weight change of the coupon according to ASTM method [24,25]:

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6 7

Time (month)

Wei

ght l

oss

(mg/

cm2)

Abioticbiotic

Fig. 4a. Weight loss as a function of time for alloy steel in biotic (natural seawater) and abiotic (filter-sterilized seawater) environment.

0

50

100

150

200

Corr

osio

n ra

te (u

m/y

ear)

250

0 1 2 3 4 5 6 7

Time (month)

Abioticbiotic

Fig. 4b. Corrosion rates as function of time for alloy steel in biotic (natural seawater) and

abiotic (filter-sterilized

seawater) environment.

75


Results of weight loss study of alloy steel showed that in abiotic environment (ASS)

th was 10.4 mg/cm2 and 24.2 mg/cm2 after 6 month of immersion respectiv after one

mon ely (Fig. 4(a). ne

mont g/cm2 after six months immersion. The results showed that the weight tic

envir and s under both conditions were observed after one

/year). The rates were then slowly

corro r corro or micr nced corrosion (MIC).

eased h

highcoup

a

h

mel corr as a

ed corr t –

hile, value

pks. ce

also conta

e plots a.

g at – ped

slow 2 mVS

otential e SCE

ore t

n o

However the weight loss of alloy steel in biotic environment (ASNS) was 13.2 mg/cm2 after oh immersion and 30.2 m

loss of alloy steel in biotic environments was relatively higher compared to that of abioonment. Figure 4(b) represents the results of corrosion rates for 6 months immersion in biotic

abiotic environment. The highest corrosion ratemonth immersion (ASS = 160.0 µm/year and ASNS = 204.3 µmdeceased (ASS = 62.7 µm/year and ASNS = 78.0 µm/year) after six months immersion. In general,

sion rates of biotic environments were higher compared to that of abiotic environment. Highesion rate under biotic environment implied that seawater was a favourable environment f

obial growth, thus were susceptible to microbiologically influe

The corrosion rate was highest after one month’s immersion after it which slowly decr time. The observation was to be expected for metal immersed in seawater. Chloride is knowit wn to

induce localised corrosion and this may explain why the corrosion of alloy steel remained relatively even after six months of exposure of the coupon in seawater (ASS = 160.0 µm/year). When the ons were immersed, the metal oxidised into solution as cations i.e., a negative charge on the l until equilibrium potential is establismet hed between metal and solution. Further possibilities were

the formation of hydroxides or oxides (corrosion products) of the metal, which formed a passive layer e surface. This condition affected corrosion causing corrosion processon t to decrease slowly.

Open Circuit Potential Measurements Results of open-circuit corrosion potential, Ecorr were measured against a standard saturated caloelectrode in the culture solution with and without SRB is shown in Fig. 5. The plot of Efunction of immersion time, shows large variations in the corrosion potentials. When filter-sterilizseawater (SW) was used as the medium, the E shifted initially to more positive values starting a582 mVSCE and decrease slowly to a constant value of – 703 mVSCE after 15 days of exposure. Wthe Ecorr of medium VMNI, the initial point value at – 644 mVSCE and then slowly dropped to a of – 824 mVSCE. Significantly higher corrosion potential was recorded in the filter-sterilized seawater com ared to VMNI medium. The presence of the yeast extract in VMNI media may explain the decrease in the corrosion potential observed over long periods of exposure, that is after two wee

rfaAccording to Feron and Dupont (1997), yeast extract may be adsorbed on the electrode suinhibiting the corrosion of alloy steel [19]. Medium VMNI also contained these anions but it

ins the organic nutrients, increasing the complexity of the system.

However, when alloy steel is exposed in VMNI inoculated with bacteria, the trends in th were very different and varied significantly with exposure time compared to VMNI not bacteri

tinIn VMNI+SRB11 medium, the Ecorr shifted to more positive values after 3 days exposure star630 mVSCE until it reached a maximum of – 513 mVSCE after 6 days. The potential then drop

ly to a value of – 658 mVSCE. The starting potential of VMNI+SRB1 was the lowest that is – 68CE and increased suddenly to a maximum value of – 548 mVSCE before decreasing slowly to a

value of – 682 mVSCE after 15 days exposure. In medium VMNI+SRB1+SRB2, the corrosion pincr ased after 4th days exposure to reach maximum values of – 530 mV after 11 days exposure.The potential then dropped slowly to a value of – 721 mVSCE. The Ecorr shifted drastically to mposi ive values after 3 or 4 days exposure in the presence of the SRB compared to that without SRB. These results showed that the composition of microbial consortia within a biofilm could play aimp rtant role in biocorrosion and that SRB isolates vary in their ability to influence the process of steel deterioration.

76


(a)

-850

-800

-750

-700

-650

-600

-550

-5000 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Incubation time (day)

Pote

ntia

l Eco

rr (m

VSC

E) Filter-sterilized seawaterVMNI

Fig. 5a. Plots of open circuit potential Ecorr as a function of immersion time in filter-sterilized

seawater and VMNI media sterile. (b)

-900

-850

-800

-750

-700

-650

-600

-550

-500

-4500 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Incubation time (day)

Pote

ntia

l Eco

rr (m

VSC

E)

VMNIVMNI+SRBIVMNI+SRBIIVMNI+SRBI+SRBII

Fig. 5b. Plots of open circuit potential Ecorr as a function of immersion time in VMNI media sterile

(control) and VMNI with some of varies bacterial inoculation of SRB.

According to the corrosion mechanism generally accepted an accumulation of sulphide as well as an increase of protons is brought about by the growth of the SRB, and this stimulated the initial dissolution of iron at quite a high rate. On the other hand, when a film of ferrous sulphide formed on the electrode surface and is trapped by biofilm layer may cause a partial inhibition in the anodic dissolution of iron. In fact, visual observation of the steel samples after being exposed to medium containing SRB show a black film over the electrode surface, while the same medium free of SRB produces a grey film and an orange yellowish precipitate. Medium VMNI also contained these anions but it also contained the organic nutrients, increasing the complexity of the system. The presence of the yeast extract may explain the decrease in the corrosion rate observed over long periods of exposure, that it after two weeks of incubation. According to Feron and Dupont (1997), yeast extract adsorbed on the electrode surface inhibits the corrosion of steel [19].

77


(a) (b) Fig. 6. SEM micrographs of alloy steel surface after four days of exposure to the SRB culture in

VMNI: (a) SRBI and (b) SRBII.

(a) (b) Fig. 7. SEM image of alloy steel surface after the removal of bacterial biofilm and

corrosion products after 15 days of exposure in VMNI media (a) without SRB culture (b) with SRB culture, showing localized corrosion.

The corrosion potential, Ecorr of alloy steel in the presence of mixed bacterial cultures are

presente

ith the bacterial species, carbon

ysis (Fig. 9)

d in Fig. 5(b). The corrosion potential of the mix-culture (SRBI and SRBII) was only slightly different than that of the pure-cultures. It has been reported that corrosion appears to be worse when a wide variety of microorganisms is present [20]. The purecultures usually induced higher corrosion rates initially, but with time the corrosion rates decreased compared to that of the control (without bacteria). In another study, it was shown that the degree of corrosion varied w

sources and the metal used [21]. SEM examination biofilm on the alloy steel’s surface showed the corrosion pitting caused of

bothing bacteria (SRBI and SRBII) of about 5-6 µm long (Fig. 6). The pit morphology of alloy steel is shown in Fig. 7. When VMNI was used in the presence of SRB (Fig. 7b), small size single pit was found compared to that of the VMNI medium without SRB. The EDS spectra of the corrosion products underneath the biofilm in the medium inoculated with and without of SRB (control) are given in Fig. 8. The presence of sulphur, most probably related with iron sulphides is obvious in the spectra corresponding to the culture medium with SRB. Analysis of EDS spectra indicates high counts of sulphur. The presence of iron sulphide in the corrosion product is confirmed by XRD anal

78


(a) (b)

Fig. 8. EDS of corrosion product: after 15 days of exposure in VMNI media (a) without SRB

(control) and (b) with SRB.

According to Anderco and Shuler (1997) [22] mackinawite is a particular form of iron sulphide that can occur frequently in immersion corrosion studies. It is known that mackinawite is produced easily from iron and iron oxides by consortia of microorganism including SRB. Moreover, the presence of mackinawite in corrosion products formed in seawater is indicative of SRB-induced corrosion [23].

It should be noted that, the importance of microbial consortia on the corrosion behaviour of

steel is a complex phenomenon requiring not only a better understanding of the ecology and physiology of biofilms but also that of electrochemical reactions at metal/biofilm interface. To date, relatively few studies have attempted to characterize biological and physicochemical processes in mix-cultural biofilms comprising of a mono-culture formed on steel. By combining field and aboratory investigations, l our research provides further evidence of the ability of naturally occurring

ence corrosion rates of steel and emphasizes the necessity of a long term monitoring of steel when exposed to microorganisms, in order to evaluate the influence of

marine environment.

compound.

consortia to influf the behaviouro

biological components in the deterioration of steel in

Fig. 9. XRD spectrum of corrosion product in Fig. 6(a) indicating mackinawite of iron sulphide

FeO-SRB

Lin

(Cou

nts)

86-0389 (C) - Mackinawite, syn - FeS - Y: 50.00 % - d x by: 1. - WL: 1.54056 - Tetragonal - I/Ic PDF 5. - 06-0696 (*) - Iron, syn - Fe - Y: 50.00 % - d x by: 1. - WL: 1.54056 - Cubic - DIF - FeO-SRB - FeO-SRB.dif - Y: 95.24 % - d x by: 1. - WL: 1.54056 - 0 - Operations: ImportFeO-SRB - File: FeO-SRB.RAW - Type: 2Th/Th locked - Start: 20.000 ° - End: 90.000 ° - Step: 0.050 ° - Step time: 1. s - Temp.: 25 °C (Room) - Time Started: 2 s - 2-Theta: 20.000 ° - Theta: 10.

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

2-Theta - Scale20 30 40 50 60 70 80 90

79


Conclusions

The following factors have been shown to be important in our study of microbially influenced corrosion of alloy steel in VMNI media. Both of SRB strains tested demonstrated the ability to corrode the alloy steel specimen at rates above that seen with an uninoculated control. Electrochemical measurements and SEM examination show that the experimentally observed strong acceleration in pitting corrosion process due to an increase in corrosion potential, induced by the both SRB strains. Under similar cultural conditions, SRB isolates vary in their ability to influence corrosion of alloy steel. Electrochemical tests and surface techniques act as a good method in analysis, giving much greater information on the biocorrosion process.

References

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13. Ive

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ller, A.R. (19 larization” y Soc 89-1696.

mild steel of suspension of Trans. Farada . 56: 16

rson, W.P. (1966) “Direct Evidence for the Cathodic Depolarization Theory by Bacterial Corrosion. Science. 151:986-988.

14. Little, B., Wagner, P. & Mansfeld, F. (1997). Microbiologically influenced corrosion. NACE International, Houston.

15. Tiller A.K. & Booth G.H. (1962) “Polarization Studies of M

16. Potekhina, J.S. (1984)

17. Romanov, B.B. (1965) “The Methods of Investigation Corrosion of Metals” Metallurgy, 280.

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18. Zinkevich, V., Bogdarina, I., Kang, H., Hill, M.A.W., Tapper, R.C. and Beech, I.B. (1996). Characterization of exopolimers produced by different isolates of marine sulphate-reducing bacteria. Int. Biodet. Biodeg. 163-172.

9. Feron, D. & Dupont. G. (1997). Novel influence of micro-organisms on the free corrosion potentials of stainless steels in natural seawater, in: D. Thierry (Ed.), EFC Publications No. 22, Aspect of Microbially Induced Corrosion, The Institute of Materials, London, pp. 103-112.

20. Franklin, M.J., Niven, D.E., Mittelman, M.W., Vass, A.A., Jack, R.F., Dowling, N.J.E., Mackowski, R.P., Duncan, S.L., Ringleberg, D.B. & White, D.C. (1989). An analogue MIC system with specific bacterial consortia, to test effectiveness of materials selection and counter-measures. Corrosion 89, NACE Proc. Conf., New Orleans, pp. 187-201.

21. Pedersen, A., Kjelleberg, S & Hermansson, M. (1988). A screening method for bacterial corrosion of metals. J. Microbiol. Meth., 8, 191-198.

22. Anderko, A. and Shuler, P.A. (1997). Computational approach to predicting the formation of iron sulphide species using stability diagrams, Computers & Geosci nces. 23 (6) 647-658.

3. Hamilton, W.A. (1994). Biocorrosion: the action of sulphate-reducing bacteria, in: C. Ratledge (Ed.), Biochemistry of Microbial Degradation, Kluwer Academic, Dordrecht.

ASTM, (1999). Standard Practice for Laboratory Immersion Corrosion Testing of Metals. American Society for Testing and Materials International, West Conshohocken, United States. Designation: G31-72.

ASTM, (2003). Standard Practice for Preparing, Cleaning and Evaluating Corrosion Test Specimens. The American Society for Testing and Materials International, West Conshohocken, United States.Designation: G1-03.

1

e2

24.

25.

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KANDUNGAN TOLUENA DAN XILENA DALAM DEBU JALAN DI SEKITAR KUALA LUMPUR

ali Othman dan Nor Faizawati Zulkifli

Pusa dan Teknologi Ma ologi Universiti Kaba UKM langor Darul E laysia.

e-mail: rozali@pkrisc km.my Abstrak: Kajian telah kehadiran tol ilena dalam de yang bersaiz <38 µm dan 38 – 63 µm di sekitar Kuala Lumpur. Kedua-dua bahan ini dipercayai digunakan dalam minyak petrol sebagai bahan tambah untu meningkatkan nombor o kedua-dua parameter kajian dari fasa pepe grafi Gas yang dilengkapi dengan Pengesan Pengionan Nyala. jian mendap tip di kawasan pusat bandar memberikan kepekatan toluena dan xilena yang le banding inggir bandar. Ujian ANOVA yang dilakukan menunjukkan bah perbeza berert a lokasi persampelan yang berbeza dari segi struktur kawasan dan bilangan kender yang melaluin an juga an saiz debu yang berbeza. Ini menunjukkan bahawa kedua-dua b pencemaran dalah lebih b setempat dan lebih bergantung kepada puncanya. Abstract: The objective of this study is to determine th tent of toluen xylene in dust (<38 µm and 38 – 63 µm in diameters) collected at variou t a Lumpur. Both pollutan e believed had been used as an additive in petrol to increase an octane number. After extraction either so or agitating method, gas chromatography completed with flame ionization detector were used to qua e amount of both parameters in street dust samples. Result obtained showed that the samples coll in urban areas rded a higher concentration of toluene and xylene. ANOVA test showed that there are a significant rences between locations due affic flows and between two diffe f du icles. Keywords:

Mohd Roz

t Pengajian Sains Kimia kanBangi, Se

an, Fakulti Sains dan Teknhsan, Mangsaan Malaysia, 43600

.cc.u

dilakukan untuk menentukan uena dan x bu jalan

k ktana petrol berkenaan. Setelah dilakukan pengekstrakan untuk mengeluarkan jal (debu) kepada fasa cecair, analisis seterusnya dijalankan menggunakan Kromato

Hasil kabih tinggi berawa terdapat

ati debu yang diku yang d dengan

an yanga d

ikutip di kawasan pi antar

taraaan ini a

yersifatahan

e cony Kual

e dan et stres sites in the vicini of ts wer

x t by ntify th

hle

ected reco diffe to tr

rent sizes o st part

street dust, toluene, xylene, analysis Pendahuluan Kemerosotan kualiti alam sekitar merupakan salah satu masalah yang semakin meruncing dari semasa ke semasa. Dunia semakin maju dan pesat membangun dalam pelbagai sektor, di mana ini secara tidak langsung akan memberikan impak yang begitu besar terhadap alam sekitar malah juga mengganggu kesihatan manusia sejagat. Pencemaran udara adalah salah satu masalah kualiti alam sekitar yang semakin parah pada masa kini. Terdapat banyak punca yang menyebabkan berlakunya pencemaran udara. Antaranya pembakaran secara terbuka, pembebasan asap daripada kilang–kilang, penggunaan kenderaan dan sebagainya. Dalam bahan pencemaran udara terkandung pelbagai jenis bahan pencemar yang berbahaya terhadap kesihatan manusia sama ada bahan-bahan organik atau bukan organik.

Debu terutamanya debu jalan raya terhasil daripada pelbagai punca. Debu jalan raya juga dikenalpasti sebagai unsur bahan pencemaran yang memberikan kesan buruk kepada manusia, haiwan dan tumbuhan. Debu boleh dikelaskan mengikut sumber dan kesannya kepada kesihatan manusia dan alam sekitar. Debu dikenali sebagai pepejal aerosol dan kebanyakannya tidak toksik [1], tetapi debu juga boleh dikatogerikan sebagai toksik jika bersaiz kurang dari 10µm [2, 3].

Debu adalah merupakan zarah–zarah kecil pepejal yang terkandung dalam udara di persekitaran. Zarah–zarah kecil ini wujud bersama–sama dengan gas, wap dan asap [4]. Debu juga boleh terhasil daripada pelbagai proses yang lain contohnya seperti daripada asap dari ekzos kenderaan, emisi dari industri dan pembakaran hutan, di mana zarah-zarah kecil ini akan bergabung dengan unsur-unsur lain di atmosfera dan membentuk zarahan yang lebih besar dan kemudian akan termendap dan membentuk debu. Debu merupakan zarah yang cuba memendap dalam masa yang agak singkat [5]. Kehadiran debu dalam udara juga adalah hasil daripada proses penyepaian mekanikal dalam proses pemecahan, peleburan atau penggerudian yang kemudiannya terampai ke udara hasil daripada percampuran dengan gas [6]. Walaupun debu jalan raya mengandungi kepekatan bahan pencemar yang tinggi, namun ia hanya mewakili penumpukan pencemar semasa [7].

Dengan adanya sifat debu yang boleh terampai, mempunyai saiz yang sangat kecil dan berkemampuan untuk termendap, maka debu boleh digunakan sebagai matriks yang sesuai untuk

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analisis tahap pencemaran udara di sesuatu kawasan. Di samping itu debu boleh terampai dalam atmosfera atau dalam gas-gas lain serta tidak boleh meresap tetapi boleh mengenap dengan pengaruh graviti [8]. Salah satu contoh analisis terhadap debu yang telah dijalankan dalam banyak kajian terdahulu ialah analisis kandungan logam berat [3, 9, 10]. Di samping itu debu juga sesuai untuk analisis bahan pencemar organik seperti toluena dan xilena kerana dipercayai terkandungan dalam minyak

bersama

16]. Menurut kajian yang telah dilakukan amaun

en persampelan adalah seperti ang diringkaskan dalam Jadual 1. Persampelan telah dilakukan sebanyak tiga kali di setiap lokasi.

Jadual 1. Kedudukan kawasan persampelan.

petrol kenderaan. Toluena dan xilena merupakan suatu bahan yang merbahaya kepada hidupan di mana

pendedahan yang maksimum kepada sebatian ini boleh memudaratkan kesihatan manusia [11]. Kedua-dua bahan ini dapat memberi kesan jangka panjang dan jangka pendek kepada manusia bergantung kepada tahap atau paras pendedahannya. Antara kesan jangka pendek ialah simptom seperti pening kepala, alergi dan muntah [12]. Manaka kesan jangka masa panjang ialah menyebabkan barah, kerosakan jantung, hati dan buah pinggang [13].

Bahan–bahan ini dipercayai ditambah ke dalam minyak petrol untuk meningkatkan nombor oktananya. Bahan ini merupakan antara bahan yang ditambah ke dalam petrol tanpa plumbum untuk menggantikan plumbum yang bersifat anti-ketuk, di mana bahan-bahan ini akan terbebas ke udara sama ada bersama asap sekiranya pembakaran tidak sempurna ke atas petrol berlaku atau akan meruap

-sama petrol sekirangnya proses peruapan berlaku [14]. Bahan pencemar ini dilaporkan terkandung dalam minyak petrol kenderaan dalam kuanttiti yang kecil, tetapi yang menjadi masalahnya kepada persekitaran ialah penggunaannya adalah tidak terhad iaitu tiada piawai yang ditetapkan untuk kedua-dua bahan berkenaan [14, 15,

toluena dan xilena yang ditambahkan ke dalam minyak petrol adalah sedikit iaitu dalam jumlah antara 0.1 – 0.6% sahaja, terutamanya apabila penggunaan petrol tanpa plumbum semakin meningkat [16].

Sehubungan dengan itu kajian ini dilakukan untuk melihat kandungan toluena dan xilena yang terdapat di permukaan debu serta mengaitkannya dengan kesesakan lalulintas sesuatu lokasi persampelan. Kawasan persampelan yang terlibat ialah kawasan bandar dan kawasan pinggir bandar Kuala Lumpur di mana kedua-dua kawasan ini mempunyai kadar kesesakan lalulintas atau bilangan kenderaan yang berbeza. Eksperimental

Lokasi Kajian Lokasi kajian atau kawasan persampelan terbahagi kepada dua kawasan iaitu kawasan bandar dan kawasan pinggir bandar. Pemilihan kawasan persampelan adalah berdasarkan kepada pemerhatian tahap kesibukan lalulintas kawasan berkenaan. Kedudukan stesen-stesy

Kategori Singkatan Stesen

PD Puduraya DM Dataran Merdeka

Kawasan bandar

BSK Perhentian bas Klang DK Danau Kota Kawasan pinggir bandar BU Bukit Unggul

Bahan kimia dan alat radas Bahan-bahan kimia utama yang digunakan dalam kajian ini adalah seperti petroleum eter (60-80oC

sebagai pelarut, toluena dan xilena (kesemuanya bergred Analar, BDH Chemical akala alat-alat radas yang digunakan ialah seperti alat-alat kaca yang berkaitan,

takat didihnya)imited). ManL

pengayak (bersaiz 38 dan 63 µm), pengekstrak soxhlet yang dilengkapi dengan didal (thimble) selulosa, penggoncang mekanikal (Grant instrument), Penyejat berputar (Bünchi Rotavapor) dan

83


Kromatografi Gas (Hewlett-Packard Company) yang dilengkapi dengan pengesan pengionan nyala sebagai pengesan untuk analisis toluena dan xilena.

an dan Pengolahan Sampel

bebas

permu

ggmakm t debu kira-kira dua kilogram diambil bagi setiap stesen. Di makmal sampel debu

lam8 µah

a kaedah pengekstarakan secara soxhlet dan penggoncangan (menggunakan

ejal [17]. Dalam

debu ah ditimbang dengan tepat) digunakan. Proses

ringkan penyejat berputar sebelum

ikuot pe

disunt

Anali

ut

Jadual 2. Pengoperasian kromatografi gas

Parameter Peralatan/Keadaan/nilai

Persampel Pengambilan debu dilakukan dengan cermat iaitu menggunakan berus dan penyodok khas yangxilena. Di mana permukaan jalan disapu secara perlahan-lahan untuk memastikan hanya debu di

kaan sahaja yang diambil. Kepanjangan jalanraya lebih kurang 100 m diperlukan untuk memastikan sampel yang cukup diperolehi. Sampel diambil di kawasan pusat bandar dan kawasan pin ir bandar. Sampel debu yang dikutip ini dimasukkan ke dalam beg plastik untuk dibawa ke

al. Beraseterusnya dipindahkan ke atas piring kertas untuk proses pengeringan di udara sekurang-kurangnya

a 72 jam untuk memudahkan proses pese ngayakan. Saiz debu yang dikehendaki adalah berukuran <3 m dan 38-63 µm. Saiz butiran debu ini diayak menggunakan pengayak bersaiz tertentu yang tel ditetapkan.

Kedua-dupenggoncang mekanikal) digunakan dalam kajian ini, dimana kedua-dua kaedah ini adalah merupakan kaedah klasik yang digunakan untuk mengekstrak bahan organik dari sampel pepkedua-dua kaedah pengekstrakan ini petroleum eter dengan takat didih dalam julat antara 60-80ºC dan

seberat lebih kurang 1.0 gram (yang telpengekstrakan ini dilakukan selama dua jam untuk kedua-dua kaedah pengekstrakan.

Alikuot sampel yang terhasil daripada proses pengekstrakan di atas seterusnya dikesehingga ke isipadu kira-kira 5 ml menggunakan alat pengeringandipindahkan ke dalam botol sampel yang bebas daripada toluena dan xilena [18]. Pemekatan alsam l ke isipadu kira-kira 1.0 ml seterusnya dilakukan menggunakan aliran gas nitrogen sebelum

ik ke dalam turus kromatografi. Sampel seterusnya dianalisis secara kualitatif dan kuantitatif menggunakan kromatografi gas.

sis Kromatografi Gas dan Kuantifikasi

an ekstraksi dianalisis menggunakan kromatografi gas (model GC-HP5890 series Lar II, Hewlett-Packard Company, USA). Keadaan pengoperasian alat kromatografi gas adalah seperti yang diringkaskan dalam Jadual 2.

Pengesan Pengesan Pengionan Nyala (FID) Turus Silika Suhu pengesan 200°C Suhu penyuntik 150°C Gas pembawa Nitrogen Masa pemisahan 40 minit

Nota: Masa pemisahan yang panjang digunakan untuk memisahkan bahan lain yang hadir bersama

Pengesanan kehadiran toluena dan xilena ditentukan berdasarkan kepada masa penahanan

bagi larutan piawainya dan juga kaedah penambahan piawai. Satu siri kepekatan larutan piawai toluena dan xilena yang sesuai digunakan untuk menyediakan lengkuk kalibrasi. Selain daripada untuk menentukan kehadiran toluena dan xilena, kaedah penambahan piawai juga digunakan untuk menentukan kepekatan toluena dan xilena dalam larutan sampel. Hasil dan Perbincangan Contoh kromatogram yang diperolehi dari analisis kromatografi gas untuk salah satu larutan sampel debu yang telah diekstrak adalah seperti yang ditunjukkan dalam Rajah 1. Manakala Jadual 3 dan 4

84


pula meringkaskan kepekatan toluena dan xilena dalam debu jalan yang telah diperolehi dalam kajian ini.

Rajah 1. Contoh kromatogram bagi sampel yang diekstrak dengan kaedah pengekstrakan soxhlet

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Jadual 3

Kepekatan (µgg-1)

. Kepekatan purata bahan cemar dalam sampel menggunakan kaedah pengekstrakan soxhlet dan pengoncangan untuk saiz debu jalan <63 µm

Kaedah pengekstrakan

Xilena Toluena Soxhlet 203 847

Penggoncangan 163 183 %(Penggoncangan/soxhlet) 80.3% 21.6%

Jadual 4. Purata kepekatan toluena dan xilena dalam sampel debu

Kepekatan (µgg-1) Saiz debu

Stesen persampelan Toluen Xilen

a a PD 163 100 DM 114 td BSK 203 172 DK 407 572

<38 µm

BU td td PD 132 183 DM 572 td BSK 491 938 DK 953 td

38-63 µm

BU td td Nota:td=tidak dapat dikesan

Dalam kajian ini dua kaedah pengekstrakan telah digunakan untuk mengekstrak sampel debu.

Kaedah pengekstrakan tersebut ialah pengekstrakan soxhlet dan penggoncangan. Kedua-dua kaedah ini adalah merupakan kaedah klasik yang digunakan untuk mengekstrak bahan organik dari sampel pepejal

si yang telah disediak purata kepekatan toluena dan xilena dalam sampel debu yang telah

[17]. Hasil analisis menunjukkan kepekatan paling tinggi bagi bahan cemar organik toluena dan xilena dikesan pada sampel debu yang diekstrak menggunakan kaedah pengekstrakan soxhlet. Ini adalah kerana kesan daripada penggunaan isipadu pelarut yang digunakan dan juga kesan dari pemanasan. Jika pelarut yang digunakan adalah banyak maka lebih banyak bahan organik yang dapat dijerap keluar daripada permukaan butiran debu begitu juga dengan pemanasan. Aspek kelarutan dan pemanasan juga mungkin memainkan peranan dalam menentukan peratus kecekapan pengektrakan. Hasil kajian juga mendapati peratus perbandingan antara kedua-dua kaedah ini adalah lebih tinggi bagi toluena berbanding xilena (Jadual 3). Keadaan ini menunjukkan bahawa toluena lebih mudah terekstrak berbanding xilena walaupun kaedah pengekstrakan yang mudah seperti penggoncangan digunakan. Analisis secara kuantitatif dilakukan untuk menghitung kepekatan kedua-dua bahan pencemar organik toluena dan xilena dalam sampel debu menggunakan kalibra

an. Jadual 4 menunjukkandigunakan.

Toluena dan xilena adalah merupakan bahan organik yang sangat berbahaya. Bahan pencemar organik ini adalah sangat bersifat sangat toksik dan memberikan kesan kepada kesihatan manusia walaupun bahan-bahan ini hanya wujud dalam kuantiti yang sedikit. Antara gejala yang wujud jika tahap dedahan tinggi kepada seseorang individu ialah sesak nafas, sakit kepala dan keletihan. Hasil daripada analisis yang telah dijalankan didapati kehadiran bahan organik berkenaan dalam kajian di dalam sampel debu jalan adalah kecil, namun ianya tidak boleh dipandang ringan kerana kedua-duanya merupakan antara bahan yang boleh menyebabkan pembentukan asbut fotokimia di udara dan ini hanya dikesan pada permukaan debu sahaja. Kandungan bahan pencemar organik berkenaan yang diperolehi dalam kajian ini adalah bergantung kepada latar belakang kawasan persampelan. Kehadiran bahan organik kajian tertinggi dapat dikesan dalam sampel dari kawasan bandar yang sibuk dengan kenderaan. Ini membuktikan bahawa bahan organik ini adalah terkandung dalam minyak petrol kenderaan.

Penggunaan kenderaan di kawasan pusat bandar adalah lebih banyak jika dibandingkan di kawasan pinggir bandar. Maka tahap kepekatan pencemaran yang disebabkan oleh toluena dan xilena

86


yang diperolehi adalah lebih tinggi di kawasan pusat bandar. Pelepasan bahan pencemar ini ke atmosfera adalah mungkin secara tumpahan minyak petrol, kebocoran enjin kenderaan atau melalui peruapan petrol. Bahan pencemar ini mempunyai sifat meruap, maka bahan-bahan ini akan meruap di atmosfera dan bergabung dengan zarah-zarah debu yang terampai di udara dan kemudiannya akan termendap secara graviti [8].

Hasil daripada kajian mendapati terdapat perbezaan kepekatan bahan organik yang dikesan bagi kawasan persampelan yang berlainan. Kandungan toluena dan xilena yang paling tinggi dapat dikesan adalah sampel kawasan pusat bandar iaitu stesen Puduraya. Kepekatan toluena dan xilena bagi stesen yang lain boleh dilihat pada Jadual 4. Bagi sampel debu dari kawasan pinggir bandar iaitu stesen Bukit Unggul tiada kehadiran toluena dan xilena dapat dikesan. Ini menunjukkan kebergantungan antara kadar penggunaan kenderaan dengan amaun bahan organik yang dikesan. Namun pegecualian dapat dilihat di stesen Danau Kota (Jadual 4). Keadaan ini berkemungkinan berlaku kerana debu di kawasan berkenaan adalah debu yang telah lama, kerana kawasan berkenaan

pusat bandar, oleh itu penumpukan toluena dan xilena berlaku. plikasi pada paras keyakinan 95% menunjukkan bahawa kawasan

tungan kepekatan bahan pencemar organik

tetap antara kandungan toluena dan xile

at dalam sampel debu jalan raya yang dianalisis. Hasil daripada analisis

dalam

mdiberikan.

tidak dibersihkan sekerap di kawasanUjian ANOVA sehala tanpa repersampelan di pusat bandar dan kawasan pinggir bandar memberi perbezaan yang bererti.

Dalam kajian ini, sampel debu yang diperoleh dari kawasan persampelan yang telah dipilih terbahagi kepada dua iaitu dengan saiz butiran bersaiz <38 µm dan 38-63 µm. Tujuan menggunakan saiz butiran debu yang berlainan ialah untuk mengetahui kebergan

yang dapat diekstrak dengan saiz butiran debu. Hasil daripada analisis yang dijalankan bagi saiz butiran debu mempengaruhi kepekatan

toluena dan xilena yang terdapat di permukaan debu berkenaan (Jadual 4). Di mana didapati saiz debu yang lebih besar iaitu antara 38-63 µm memberikan kepekatan toluena dan xilena yang lebih tinggi (kecuali ada lokasi terentu memberikan nilai yang sebaliknya) (Jadual 4). Ini mungkin disebabkan oleh peratus fraksi yang bersaiz <38 µm adalah kecil dan berbeza antara lokasi. Contohnya kawasan yang berpasir mempunyai saiz butiran debu bersaiz kecil yang lebih rendah dan begitu juga sebaliknya. Ujian ANOVA satu hala tanpa replikasi pada paras keyakinan 95% menunjukkan bahawa secara amnya terdapat perbezaan yang bererti antara saiz butiran debu, iaitu debu yang bersaiz 38-63 µm memberikan kepekatan toluena dan xilena yang lebih tinggi berbanding debu bersaiz <38 µm bagi hampir kesemua lokasi kajian.

Hasil kajian juga mendapati bahawa tidak terdapat trend yang na (Rajah 3). Namun berdasarkan kepada Rajah 3, dapat dilihat dengan lebih jelas bahawa

sekiranya kaedah pengekstrakan soxhlet digunakan kandungan xilena adalah lebih tinggi berbanding dengan toluena. Keadaan ini menunjukkan bahawa terdapat kemungkinan penggunaan xilena yang lebih tinggi berbanding toluena dalam petrol dan juga mungkin kerana xilena lebih sukar meruap di

dara, menjadikannya lebih mudah termendap pada zarah-zarah debu. u Kesimpulan Secara keseluruhannya, hasil daripada kajian yang telah dijalankan mendapati bahan pencemar oganik seperti toluena dan xilena terdap

terhadap sampel debu dilakukan didapati kepekatan bahan pencemar organik toluena dan xilena yang paling tinggi dapat dikesan adalah di kawasan pusat bandar. Perbezaan kedua-dua kawasan persampelan ini adalah dari segi kesibukan kenderaan, maka ini membuktikan bahawa kehadiran bahan pencemar organik ini adalah berpunca daripada minyak petrol kenderaan. Penggunaan dua kaedah pengekstrakan yang berbeza menunjukkan bahawa toluena lebih mudah diekstrak berbanding dengan xilena. Saiz butiran juga mempengaruhi kandungan toluena dan xilena

debu jalan. Secara amnya kandungan xilena juga adalah lebih tinggi berbanding dengan toluena dalam debu jalan yang digunakan yang mungkin disebabkan oleh pengunaannya yang lebih meluas.

Penghargaan Penulis ingin merakamkan ribuan terima kasih kepada semua yang terlibat secara langsung dalam

enjayakan penyelidikan ini. Terima kasih juga kepada pihak UKM kerana bantuan kewangan yang

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3. Rozali, M.O., Mohamed Nazir Ramlan (2000) “Analisis Kandungan Logam Berat dalam Dampel Debu Jalan Raya di Sekitar Kuala Lumpur, Kajang, Bandar Baru Bangi, Bangi Lama, Nilai dan Seremban”. Malays. J. Anal. Sci. 6(1). 112-119.

4. Laharne, S., Charleswort,

5. uala Lumpur: Dewan Bahasa DR.C. (1985) “The Relationshis, B.E., Elwood, P.C., Gallacher, J.E.

oils an House Dust in an Old Lead Minnini

een Heavn. Pollut.a of North Wales, Great Brita

7. Harrison, R.M., Mora, S. J., Rapsomakins, S., JohnsSciences”, New York: Cambridge University Press.

8. Zaini, H. (1997) “Pengenalan Pencemaran Udara”. Kuala Lumpur: Dewan Bahasa Dan Pustaka 9. Rozali, M. O., Mohd Kamal Md. Zin (1997) “Kandungan Logam Berat Dalam Debu Jalan Di Sekitar Bandar Kota

Kinabalu, Sabah”. Malays. J. Anal. Sci. 3(1). 101-112. 10. Massadeh, A.M. (2003) “ Distributions of Copper and Zinc in Different Fractions of Particle Sizes in Road Dust

Samples in Irbid City, Jordan using Atomic Absorption Spectrometry” Res. J. Chem. Environ. 7(4). 49–54. 11. Dictionary Organic Compaunds (1983) Ed. Ke-5. New York: Chapman & Hall. 12. Butler, J.D. (1979) “Air Pollution Chemistry”, London: Academic Press. 13. Kupchella, C.E., Hyland, M.C. (1993) “Environment Science: Living within the System of Nature”, Ed. Ke-3 14. Simons, C. (1995) “The Lies of Unleaded Petrol - Part 2. Highly Toxic Chemicals are Replacing the Lead in Our

Fuel, yet Government Authorities Continue to Underestimate the Serious Risks to Public Health” NEXUS Magazine.. 2(26). http://www.nexusmagazine.com/articles/ulp2.html

15. Crabtree, J.M, Roziah Hj. Mohamed, Zani bin Assim (1997) “Aromatics (Benzene, Toluene and Xylene) and Oxygenate (Methly tert-Butyl Ether) Contents in Unleaded Gasoline. Abstracts 2nd International Conference on E

dier, C., Laurent, C. (2003) “Solvent Extraction of Organic Molecules of logical Interest for in-situ Analysis of the Martin Soil” J. Chromatogr. A(999). 165-174.

nvironmental Chemistry and Geochemistry In The Tropic (Geotrop)”, hlm. 31. Kuala Lumpur: Malaysia. 16. Kokosa, J.M., Andrzej, P. (2002) “Headspace Microdrop Analysis- An Alternative Test Method for Gasoline Diluent

and Benzene, Toluene, Ethlybenzene and Xylenes in used Engine Oils” J. Chromatogr. 983. 205-214. 17. Dean, J.R., Guohua Xiong, (2000) “Extraction of Organic Pollutants from Environmental Matries: Selection of

Extraction Technique” Trends in Anal. Chem. 19(9). 553-558. 8. Buch, A., Sternberg, R., Meunier, D., Ro1

Exobio

88

Pulau Ti

t

atmosfer

Abstrac

were me e

210

210 238

g210 210

ersekita k zooplankton dan ketumpatan zooplankton di ermukaan air (Tateda et al. 2003). Akan tetapi 210Pb adalah terhasil di atmosfera dan melekat kepada partikel

organik yang halus. Maka sifat 210Pb dalam sistem akuatik lebih dipengaruhi oleh pemendakan aluminosilikat seperti partikel tanah liat dan debu dalam turus air (Hung & Chung, 1998). Oleh itu, dua nuklid ini merupakan penyurih yang sesuai untuk partikel organik dan inorganik yang halus di persekitaran marin. Di laut terbuka, keseimbangan di antara 210Po dan 210Pb di turus air mencapai hampir tahap yang stabil kerana (i) beban sedimen yang rendah di mana ia mengawal proses skaveng untuk kedua-dua nuklid, (ii) produktiviti biologi yang rendah di mana ia menyekat fluks penurunan kedua-dua nuklid dengan ‘fecal pellet’ dan penenggelaman serpihan biogenic dan (iii) input 210Po dari atmosfera dalam kuantiti yang sangat rendah (Tateda et al. 2003). Akan tetapi, keseimbangan antara kedua-dua nuklid ini di tepi pantai atau estuari adalah berubah-ubah kerana input 210Po dengan beban sedimen di sungai, proses skaveng untuk 210Pb yang terhad oleh gangguan lateral 210Pb di kawasan air terbuka, kehilangan 210Po secara peruapan biologi dari permukaan air

210PO/210PB DALAM AIR HUJAN, AIR SUNGAI DAN AIR LAUT

Che Abd Rahim Mohamed, Wong Fatt Yin dan *Zaharuddin Ahmad Pusat Pengajian Sekitaran & Sumber Alam

Fakulti Sains & Teknologi Universiti Kebangsaan Malaysia

43600 Bangi, Selangor

*Malaysian Institute Technology Nuclear (MINT) Bangi, Selangor.

E-mail: [email protected] ohamed6566@y, m ahoo.com

: Kajian ini bertujuan untuk menentukan aktiv 210Po d 210PbAbstrak iti an dalam air hujan, air sungai dan air laut. Kawasan persampelan air hujan dan air sungai terletak di sekitar Kajang-Bangi, Selangor manakala air laut di

elangor dan Pulau Tinggi, Johor. Aktiviti 210Po dan 210Pb dalam sampelKapar, S air ditentukan dengan menggunakan Spektrometer α dan pembilang αβ paras rendah. Julat aktiviti 210Po dalam air laut di Kapar dan

nggi masing-masing adalah 0.020-0.153 dpm/L dan 0.046-0.216 dpm/L. Hasil kajian menunjukkan perbezaan aktiviti 210Po dalamterdapat kedua-dua kawasan yang dikaji berpunca daripada keadaan geografi dan

aktiviti yang berlaku di kawasan tersebut. Manakala aktiviti 210Po dalam air hujan dan air sungai adalah agak ngan julat aktiviti masing-masing ialah 0.117-0.598 dpm/L tinggi de dan 0.111-0.251 dpm/L. Pelepasan sisa

industri dan kenderaan bermotor ke atmosfera adalah faktor yang mempengaruhi aktivi i 210Po dalam air hujan ungai. Untuk aktiviti 210Pb pula, julat aktivitinya dan air s pada air laut di Pulau Tinggi adalah di antara 0.046-

0.126 dpm/L dengan purata 0.087 dpm/L. Aktiviti 210Pb di Pulau Tinggi adalah berpunca daripada input Pb dari a ke permukaan lautan. Dalam kajian ini, corak bagi jumlah keseluruhan aktiviti 210Po yang ditunjukkan ga-tiga sampel ialah air hujan> air sungai>oleh keti air laut.

t: This study was carried out to determine the activity of 210Po dan 210Pb in rainwater, river and . The sampling area foseawater r rainwater and river water was collected from Kajang-Bangi, Selangor

meanwhile seawater from Kapar, Selangor and Pulau Tinggi, Johor. Activity of 210Po and 210Pb in water sample asured using spectrom ter α and low background αβ counting system. The activity range of 210Po in

seawater from Kapar and Pulau Tinggi are found to be 0.020-0.153 dpm/L and 0.046-0.216 dpm/L respectively. The result from this study showed a different activity of 210Po in both areas. The variation was due to geography

210condition and the activities in that area. On the other hand, the activity of Po in rainwater and river water was a bit high with a range of 0.117-0.598 dpm/L and 0.111-0.251 dpm/L respectively. Industrial and automobile waste releases to atmosphere were the factor which influenced the activity of Po in rainwater and river water. Meanwhile, the activity range of 210Pb in seawater collected from Pulau Tinggi was 0.046-0.126 dpm/L with

210mean concentration of 0.087 dpm/L. The activity of Pb in Pulau Tinggi was caused by the input of Pb from atmosphere to sea surface. In this research, the pattern of total activity of three samples is rainwater > river water > seawater.

Pendahuluan 210Po dan Pb merupakan ahli kepada siri reputan U yang mana pereputannya berlaku secara semulajadi.

Sebelum ini, 210Po dan 210Pb merupakan dua unsur yang paling banyak di unakan sebagai penyurih radioaktif untuk mengkaji proses-proses biogeokimia. Po dalam persekitaran marin merupakan produk reputan Pb yang kebanyakannya diserap oleh zooplankton dan melekat pada partikel organik. Maka sifat 210Po dalam

ran marin adalah berkaitan dengan aktiviti metabolipp

(Momoshima et al genik dan proses pengaliran atasan.

n kajian lah untu rub ktiviti dalam t ang berbeza iaitu air huja an air l mping unt buat p ra kawasan persampelan t

Persampelan dan penga n

Tiga jenis samp l air telah diambi lam kajian in sampel air laut, a tiga-tiga jenis sampel ai kumpul dari lok ang berlain dual 1) pel ai a lokasi iaitu di Kapar, Selangor dan Pulau ggi, Johor ( ). Kap rupak pantai barat Semenan ng Malaysia manakala Pulau Tin erupak uah ut China Selatan. Sebanyak 8 stesen dipilih u k melakukan pelan par da

Sampe r sungai pula d bil di sepan ungai t yan e Bangi, Selangor (Rajah ). Sebanyak enam esen sampel a ai diam sepa mengalir dari Kajang ke Bangi, Selangor d el air pula di l di angsaan Malaysia, Selan

210Po dan 21 berpanduka da kaed eng a iviti 210Po dibi enggunaka lfa-spektrom G & G TEC) 24 jam untuk setiap . Baki larutan d m bikar selepas pemendap an Pb iaitu melalui prose isahan resin kat rja-kerja ilangan -β dil bilangan spektrometer gross α/β, Model LB 0-W, TENN dan m mbila k setiap sampel.

Keputusa erbinc Aktiviti 210 air laut

P Johor Julat aktiv g diperolehi daripada lapisan permukaan, pe gahan adalah 0.057-0.096 dpm/L, 0.059-0.122 dp an 0.046-0.216 dpm/L. kala p iperolehi masing-masing adalah 0.074 dpm /L dan 0.100 Sec iti 210Po tertinggi wujud pada lapisan dasa da stesen 5 de gan nilai 0.216 dpm iti 210Po terendah pula berlaku pada lapisan ukaan lautan.

Pulau Tinggi yang terletak Laut China Selatan adalah h pul utan luas dan terbuka nggi juga merupakan sebuah pu u yang tela di iktira an Laut

cemaran da luaran rkenaan. dah (Nozaki et al. 1991). Maka ini akan mengurangkan

aktiviti 210Po pada permukaan lautan. Aktiviti 210Po yang rendah pada lapisan permukaan juga berkemungkinan adalah kerana proses biologi

yang terlibat di kawasan berkenaan. Ini adalah kerana aktiviti 210Po adalah berhubung kait dengan aktiviti metabolik zooplankton dan ketumpatan zooplankton di permukaan air (Jefree et al. 1997). Maka permindahan 210Po dari permukaan dikawal oleh aktiviti biologi dan proses skaveng yang terlibat (Heussner et al. 1990; Tateda et al. 2003). Aktiviti 210Po dan 210Pb yang tinggi pada fasa terlarut pada dasar lautan juga ditingkatkan oleh proses pemendapan sedimen dari permukaan dan sumber Pb terlarut di dasar (Theng & Mohamed 2005). Oleh itu, aktiviti 210Po yang lebih tinggi wujud di bahagian dasar berbanding permukaan lautan.

Kapar, Selangor Julat aktiviti yang diperolehi pada lapisan permukaan dan lapisan dasar masing-masing adalah di antara 0.020-0.153 dpm/L dan 0.029-0.081 dpm/L dengan nilai purata 0.064 dpm/L pada permukaan air dan 0.058 dpm/L pada lapisan dasar. Secara puratanya, aktiviti 210Po adalah lebih tinggi di lapisan permukaan berbanding dengan lapisan dasar. Keadaan ini adalah berbeza dengan aktiviti 210Po di Pulau Tinggi, Johor di mana aktiviti 210Po adalah lebih tinggi di lapisan dasar berbanding lapisan permukaan air (Rajah 3).

Kapar terletak di estuari Sungai Kapar Kechil berhampiran dengan Selat Melaka. Ia merupakan sebuah kawasan penjanaan kuasa elektrik yang menggunakan arang batu. Kawasan ini tercemar dengan sisa buangan dari stesen penjanaan kuasa elektrik melalui asap yang disalur ke atmosfera dan air panas yang disalur terus ke lautan. Sumber utama pembebasan radioaktif dari pembakaran arang bukan U dan Th sahaja, tetapi juga produk yang dihasilkan dari reputan radioaktif seperti radium, radon, polonium, bismuth dan plumbum (Gabbard 2002). Maka peningkatan aktiviti 210Po pada lapisan permukaan air adalah berpunca daripada input dari atmosfera yang kebanyakan sumber poloniumnya datang dari proses pembakaran arang batu. Selain itu, sumber polonium di atmosfera juga wujud dari proses pereputan 222Rn (Yang dan Lin 1992) yang memasuki perairan atau kembali ke permukaan bumi melalui pemendapan kering dan air hujan (Peck & Smith 2000).

Di samping itu, aktiviti 210Po di persisiran juga dipengaruhi oleh tindakan ombak, faktor geologi dan input dari aliran air taw n kawasan Kapar yang

. 2001), dan pembentukan 210Po dari degradasi berterusan partikel bio

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ar (Wildgust et al. 1998; Theng & Mohamed 2005). Peraira

merupakan kawasan estuari banyak menerima input dari Sungai Kapar Kechil dan Sungai Kapar Besar. Ini dapat men 210 aitu 0.153 dpm/L.

Aktiviti 210Po yang rendah wujud pada lapisan dasar lautan kecuali stesen 7 dengan nilai purata 0.058 dpm/L. Kap pakan an ked 10 m iran yang cetek pro puran y berpunca rus air da ombak se aku y m ebabkan pencampuran dimen dasar dengan ai . Ini menyebabkan kandun olonium tidak termendak ke dasar tetapi m ir kemba mukaan

Pad n 7, akt adalah i dasar kat dpm/L ing lapisan permukaan /L. S merupa asi pers yang b n deng sini, jeti digunakan se kawasan erlabuh enurunk gannya rang b dibawa ke daratan. Semasa angkutan, kem nan arang uh ke lautan d n mendak ke d enyebabkan aktiviti 210Po tinggi di da tan. Di itu, si uang kapal ang terjatuh aut dan me ak juga boleh menyebabka an po ertamb

Aktiviti 210P r su

Kajan angi, SelangStesen persa ni terl kitar S ngat yang m ngalir dari Ba ar Kajang ke angi. Daripada maklumat an yang dip idapa i 210Po dalam air sungai adalah tinggi dan bertabur secara tidak seraga semua ang di t aktivi yang di alah 111 dpm/L hingga 0.251 engan ktiviti 2 m/ 4).

Dalam kajian ini, nilai aktiviti Po dalam air su ai yang dipe lehi adalah ak tinggi. Di persekitaran r Kajang ui baha ar ini m n suatu ang se penuhi oleh kenderaan b r. Pengg lumbum il dalam en kenderaan, pembakaran mi ak fossil serta hasil buanga m fosfat ening epekatan 210 dan 210Pb da persekitaran akuatik melalui atmosfera ( ski & ec 200 samping wasan ang m n kawasan perindustrian j a menyumban kepada kandungan polonium e dalam sung i. Aktiviti 0Po meningkat dalam sistem ik keran asan da dustri (C 1997) masuki ecara terus atau melalui era.

Akt Po di se sungai paling ting ujud pad 4 deng katan 0.261 dpm/L. Ini ungkin da asan asap yang banyak ri kilang pa ang dibina berdekatan d esen p an berk i akan men kan penin atan penyerap partikel 210Po pada kawasa enaan. D itu, b gkinan juga kilang ini me urkan sisa b gannya terus ke dalam sun nyebabk katan ya i wujud di sen ini.

Akt Po yang ujud d taran Sung juga d at dijelaskan ngan merujuk kepada keputusan untuk aktiviti Po dalam air hujan yang diperolehi. Aktiviti 210Po dalam air hujan juga menunju 0Po pada air sungai.

awasan persampelan air hujan juga adalah berdekatan dengan tempat persampelan air sungai. Maka interaksi tmosfera dan air hujan dapat mempengaruhi dan menjelaskan aktiviti 210Po yang wujud dalam air sungai.

ktiviti 210Po dalam air hujan di UKM, Bangi asil kajian untuk aktiviti 210Po dalam air hujan dari 6 tarikh persampelan telah diperolehi (Rajah 5). Daripada eputusan ini didapati aktiviti 210Po dalam air hujan adalah agak tinggi dan taburannya adalah secara tidak ragam mengikut tarikh persampelan. Julat aktiviti 210Po yang diperolehi adalah antara 0.117-0.598 dpm/L

engan purata aktiviti 0.277 dpm/L. Kawasan Kajang dan Bangi merupakan kawasan daratan yang luas dan pesat dengan pembangunan.

0Po dan 210Pb wujud di atmosfera sebagai produk pereputan gas 222Rn yang mengalir keluar dari daratan atau erak bumi (Cochran 1998). Aktiviti 222Rn pada udara di kawasan daratan adalah lebih kurang 102 kali lebih nggi daripada aktiviti 222Rn pada udara di kawasan perairan (Tateda et al. 2003). Di samping itu, aerosol yang ma terkandung di atmosfera memperlihatkan sumber yang signifikan untuk 210Po dan 210Pb di atmosfera okeida et al. 1996). Oleh itu, tempoh tidak hujan yang lebih lama akan menyebabkan penambahan kandungan

0Po di atmosfera. Sumber kemasukkan 210Po ke atmosfera telah dicadangkan melalui pembakaran biomass (Le Cloarec et

l. 1995), letupan volkanik (Nho et al. 1996), pelepasan industri (Carvalho 1995) dan proses peruapan 210Po cara biologi dari perairan (Tateda et al. 2003). Di persekitaran kawasan persampelan, kehadiran 210Pb dalam

ir hujan adalah kemungkinan besar datang dari proses pembakaran biomass dan pelepasan sisa industri. Ini erana kawasan persampelan air hujan berdekatan dengan kawasan bandar dan perindustrian. Di samping itu, erlepasan 210Po ke atmosfera melalui pembakaran boleh mencapai 100 kali ganda berbanding pemeruapan 0Po secara semula ja bert et al. 1985). Maka jelaslah bahawa sumber utama aktiviti 210Po dalam air

jelaskan bahawa lapisan permukaan stesen 5 menerima aktiviti Po yang paling tinggi i

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hujan adalah berpunca dari pembakaran petrol oleh kenderaan dan pelepasan dari kawasan industri (Stepnowski & Skwarzec 2000).

Hasil kajian ini mempunyai nilai yang signifikan dengan keputusan aktiviti 210Po dalam air sungai (Rajah 4.3 dan Rajah 4.4). Kedua-dua keputusan menunjukkan nilai aktiviti 210Po yang agak tinggi di mana purata aktiviti 210Po untuk air hujan dan air sungai masing-masing adalah 0.277 dpm/L dan 0.160 dpm/L. Oleh kerana tempat persampelan antara air hujan dan air sungai adalah sama, maka wujud kaitan interaksi antara air hujan dengan air sungai yang mengalir di permukaan bumi.

Daripada kedua-dua keputusan, kita dapat andaikan secara puratanya hampir 58% daripada aktiviti 210Po di atmosfera akan memasuki sistem sungai apabila hujan turun. Selainnya iaitu 42% daripada aktiviti 210Po di atmosfera akan hilang ke persekitaran seperti meresap masuk ke dalam tanah, diserap oleh akar tumbuhan dan sebagainya. Keadaan ini dihitung dengan andaian bahawa tiada input 210Po lain yang memasuki sistem sungai melalui persamaan di bawah.

aktiviti 210Po di air sungai % input 210Po melalui air hujan ke sistem sungai

=aktiviti 210Po di air hujan

x 100%

Aktiviti 210Pb dalam air laut di Pulau Tinggi, Johor

Aktiviti 210Pb dalam air laut di Pulau Tinggi bagi 6 stesen ditunjukkan dalam Rajah 6. Keputusan yang diperolehi aktiviti 210Pb dalam air laut juga tertabur secara tidak konsisten. Julat aktiviti 210Pb untuk lapisan permukaan, pertengahan dan dasar air masing-masing adalah antara 0.026-0.126 dpm/L, 0.072-0.125 dpm/L dan 0.046-0.120 dpm/L dengan purata aktiviti 210Pb masing-masing adalah 0.093 dpm/L, 0.079 dpm/L dan 0.070 dpm/L. Secara puratanya, tiada perbezaan aktiviti 210Pb yang ketara diperlihatkan di antara ketiga-tiga lapisan dan ini mungkin menunjukkan proses percampuran yang sempurna telah berlaku di lautan Pulau Tinggi.

Untuk lapisan permukaan, input 210Pb adalah berkemungkinan dari atmosfera. 210Pb terbentuk di ng terbebas dari kerak bumi. Pb dengan

n kawal oleh proses yang bertindak terhadap ol yang membawanya seperti sistem angin dan kadar kejatuhan di atmosfera berbanding reputan

radioaktifnya (Paatero et al. 2003). Maka, 210Pb yang dibawa dari daratan oleh tiupan angin memasuki permukaan lautan sebelum ia sempat mereput dan menyebabkan kandungan 210Pb yang tinggi di permukaan air.

Di samping itu, didapati ralat yang diperolehi bagi sesetengah lapisan adalah mencatatkan nilai yang lebih tinggi daripada hasil. Ada juga sesetengah lapisan yang tidak dapat diketahui nilai sebenar aktiviti 210Pb seperti lapisan permuaan stesen 2 dan 3, lapisan pertengahan stesen 4, lapisan dasar stesen 5 dan ketiga-tiga lapisan untuk stesen 6. Keadaan ini adalah disebabkan oleh nilai latar belakang yang tinggi dan nilai sampel yang agak rendah pada lapisan berkenaan. 210Po/210Pb Julat nisbah 210Po/210Pb untuk lapisan permukaan, pertengahan dan dasar air di Pulau Tinggi masing-masing adalah antara 0.450-2.831 dpm/L, 0.558-7.556 dpm/L dan 0.603-1.705 dpm/L. Secara keseluruhannya aktiviti 210Pb adalah jauh lebih rendah berbanding dengan aktiviti 210Po (Jadual 2).

Keputusan ini menunjukkan bahawa terdapat lebihan kemasukan polonium-210 berbanding plumbum-210 untuk setiap lapisan yang telah ditafsirkan. Secara umumnya, nisbah 210Po/210Pb dalam kawasan pantai adalah lebih tinggi daripada uniti iaitu satu. Ini adalah kerana terdapat satu pengayaan 210Po berkaitan 210Pb yang tidak boleh dijelaskan oleh input asas mereka dari atmosfera kerana nisbah 210Po/210Pb di atmosfera adalah kira-kira 0.1 (Gasco et al. 2002). Di samping itu, sifat kimia yang berbeza bagi kedua-dua radionuklid di turus air adalah digambarkan oleh afiniti yang kuat bagi 210Po terhadap partikel berbanding 210Pb (Gasco et al. 2002).

Kesimpulan Kajian mendapati jumlah aktiviti 210Po yang ditunjukkan oleh ketiga-tiga jenis sampel air ialah; air hujan > air sungai > air laut. Andaian bahawa aktiviti 210Po yang berada di atmosfera akan turun ke bumi bersama air hujan dan di permukaan bumi ia akan meresap ke dalam tanah atau memasuki aliran air permukaan seperti sungai dan akhirnya 210Po akan memasuki lautan melalui aliran sungai. Terdapat kehilangan aktiviti 210Po ke persekitaran semasa ia diangkut dari atmosfera ke lautan iaitu jumlah aktiviti adalah menurun dari atmosfera ke lautan.

Penghargaan Universiti

a rima kasih ga ke IPRA: 09-02-02-0045-EA141

atmosfera melalui reputan radioaktif gas 222Rn (T1/2 = 3.8 hari) yaparuh hayat yang pa jang, pengeluarannya dari atmosfera lebih di

210

seaeros

Setinggi-tinggi penghargaan dan ribuan terima kasih diucapkan kepada kakitangan makmal ebangsaan Malaysia d n Malaysian Institute for Nuclear Technology di atas bantuan yang diberi. TeK

ju

Rujukan Carvalho, F.P. 1995. Origins and concentrations of 222Rn, 210Pb, 210Bi and 210Po in the surface air at Lisbon,

Portugal, at the Atlantic edge of the European continental landmass. Atmospheric Environment. 29: 1809-1819.

Carvalho, F.P. 1997. Distribution, cycling and mean residence time of 226Ra, 210Pb and 210Po in the Tagus estuary. Sci. Total Environ. 196: 151-161.

Cochran, J.K., Frignani, M., Salamanca, M., Belluucci, L.G. & Guerzoni, S. 1998. Lead-210 as a tracer at atmospheric input of heavy metals in the northern Venice Lagon. Marine Chemistry 62: 15-29.

Gabbard, A. 2002. Coal Combustion: Nuclear Resources or Danger. (atas talian) http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html (25 Feb 2005)

Gasco, C., Anton, M.P., Delfanti, R., Gonzalez, A.M., Meral, J. and Papucci, C. 2002. Variation of the activity concentrations and fluxes of natural (210Po, 210Pb) and anthropogenic (239,234Pu, 137Cs) radionuclides in the Strait of Gibraltar (Spain). J. Environ. Radioactivity. 62: 241-262.

Heussner, S., Cherry, R.D. & Heyraud, M. 1990. 210Po, 210Pb in sediment trap particles on a Mediterranean continental margin. Continental Shelf Research. 10: 989-1004.

Hung, G.W. & Chung, Y.C. 1998. Particulates fluxes, 210Pb and 210Po measured from sediment trap samples in a canyon off northeastern Taiwan. Continental Shelf Research. 18: 1475-1491.

Jeffree, R.A., Carvalho, F., Fowler, S.W. & Farber-Lorda, J. 1997. Mechanism for enhanced uptake of radionuclides by zooplankton in French Polynesian oligotrophic waters. Environmental Science and Technology. 31: 2584-2588

Lambert, G.M., Le Cloarec, F., Ardouin, B. & Bonsng, B. 1985. Volcanic emission of radionuclides and magma dynamics. Earth and Planetary Science Letters. 76: 185-192.

Le Cloarec, M.F., Ardouin, B., Cachier, H., Liousse, C., Neveu, S. & Nho, E.Y. 1995. 210Po in savanna burning plumes. J. Atmospheric Chemistry. 22: 111-122.

Momoshima, N., Song, L.X., Osaki, S. & Maeda, Y. 2001. Formation and emission of volatile polonium compound by microbial activity and polonium methlation with methyl-cobalamin. Environmental Science and Technology. 35: 2956-2960.

Nho, E.Y., Ardouin, B., Le Cloarec, M.F., Ardouin, B. & Tjetjep, W.S. 1996. Source strength assessment of volcanic trace elements emitted from Indonesian arc. Journal of Volcanology and Geothermal Research. 74: 121-129.

Nozaki, Y., Tsubota, H., Kasemsupaya, V., Yashima, M. & Ikuta, N. 1991. Residence times of surface water and particles-reactive 210Pb and 210Po in the East China and Yellow seas. Geochimica et Cosmochimica Acta. 55: 1265-1272.

Paatero, 10 concentration in the air at Mt. Sv 28: 1175-1180.

eck, G.A. and Smith, J.D. 2000. Determination of 210Po and 210Pb in rainwater using measurement of 210Po and 210Bi. Journal of Analytica Chimica Acta. 422: 113-120.

Stepnowski, P. & Skwarzec, B. 2000. A comparison of 210Po accumulation in mollusks from the southern Baltic, the coast of Spitsbergen and Sasek Wielki Lake in Poland. J. Environ. Radioactivity. 49: 201-208

Tateda, Y., Carvalho, F. P., Fowler, S. W. & Miquel, J. C. 2003. Fractionation of 210Po and 210Pb in Coastal Waters of the NW Mediterranean Continental Margin. Continental Shelf Research 23: 295-316.

Tokeida, T., Yamanaka, K., Harada. K. & Tsunogai, S. 1996. Seasonal variations of residence time under upper atmospheric contribution of aerosols studied with Pb-210, Bi-210, Po-210 and Be-7. Tellus. 48B: 690-701.

Wildgust, M.A., McDonald, P. & White, K.N. 1998. Temporal changes of 210Po in temperate coastal waters. Sci. Total Environ. 214: 1-10.

Yang, C.H. & Lin, H.C. 1992. ead-210 and Polonium-210 across the frontal region between Kuroshio and East China Sea, Northeast of Taiwan. TAO 3 (3): 379-394.

J., Hatakka, J., Holmen, K., Eneroth, K. & Viisanen, Y. 2003. Lead-2Zeppelin, Ny-Alesund, albard, J. Physics and Chem. Of the Earth.

P

Jadual 1. Lokasi stesen-stesen persampelan yang dilakukan semasa kajian

Lokasi Nama Tempat Stesen Kedala an Jisim ongitud)

Kapar 6'44"U 101°20'06"T

mAir, m Air, L (Latitud, L

1 2.3 m 15 L 03°0 21 Julai 2004 6'39"U 101°19'52"T

3 03°07'40"U 101°19'03"T

7 4.2m 15 L 03°06'33"U 101°19'00"T

2 - 15 L 03°00.8m 15 L

4 8.3m 15 L 03°05'35"U 101°20'19"T 5 9.5m 15 L 03°06'00"U 101°19'41"T 6 4.8m 15 L 03°06'25"U 101°19'08"T

8 4.1m 15 L 03°07'37"U 101°18'41"T Pulau Tinggi 1 30m 15L 02°15'56"U 104°05'59"T 14-22 Ogos 2 30m 15L 02°18'01"U 104°05'02"T

2004 3 21m 15L 02°16'15"U 104°08'43"T 15L 02°18'43"U 104°08'35"T

5 23m 15L 02°17'25"U 104°09'40"T 6 27.9m 15L 02°19'58"U 104°07'54"T

4 25m

Kajang* 1 15L 02°59'30"U 101°47'53"T 4 Nov 2004 2 15L 02°59'29"U 101°47'30"T

3 15L 02°59'37"U 101°47'06"T

4 15L 02°57'51"U 101°47'02"T

5 15L 02°55'53"U 101°46''33"T

6 15L 02°55'06"U 101°45'33"T

UKM** 02°56'02"U 101°46'51"T (*) sampel air sungai dan (**) sampel air hujan.

PulauTinggi

Kajang-Bangi

Kapar

PulauTinggi

Kajang-Bangi

Kapar

Rajah 1. Peta menunjukkan lokasi persampelan

Jadual 2. Aktiviti 210Po, 210Pb dan nisbah 210Po/210Pb dalam air laut di Pulau Tinggi, Johor

Stesen Aktiviti Po-210, dpm/L Aktiviti Pb-210, dpm/L (Lapisan) ralat ralat

210Po/210Pb

1 (S) 0.0736 0.0954 0.0260 0.0007 2.8309 (M) 0.1220 0.1350 0.1253 0.0017 0.9737 (B) 0.0871 0.1140 0.0629 0.0013 1.3861

2 (S) 0.0670 0.0984 - - - (M) 0.0589 0.0807 0.0723 0.0013 0.8149 (B) 0.0463 0.0921 0.0455 0.0011 1.0171

3 (S) 0.0738 0.1720 - - - (M) 0.0605 0.0978 0.1085 0.0016 0.5576 (B) 0.0881 0.1252 0.0516 0.0010 1.7048

4 (S) 0.0566 0.0921 0.1259 0.0020 0.4498 (M) 0.0649 0.1839 - - - (B) 0.0727 0.1045 0.1205 0.0018 0.6030

5 (S) 0.0776 0.1228 0.1276 0.0016 0.6079 (M) 0.0709 0.1142 0.0094 0.0005 7.5557 (B) 0.2162 0.3001 - - -

6 (S) 0.0957 0.1435 - - - (M) 0.0816 0.1366 - - - (B) 0.0886 0.1364 - - -

S, M dan B masing-masing mewakili lapisan rmukaan, pertengahan dan dasar.

Rajah 2.

pe

Aktiviti 210Po dalam air laut di Pulau Tinggi, Johor

Stesen1 2 3 4 5 6

210 Po

, dpm

/L

0 .05

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Permukaan Pertengahan Dasar

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iviti

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iviti

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/L

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StesenPermukaan Dasar

Rajah 3. Aktiviti 210Po dalam air laut di Kapar, S

elangor

1 2 3 4 5 6

k 21

0 Po, d

pm/L

tiviti

A

0.05

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Stesen

0.10

0.15

0.20

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0.30

ktiviti 210Po dalam air sungai mengikut stesen di Kajang-Bangi Selangor

Rajah 4. A

Tarikh

25-Okt 2-Nov 3-Nov 25-Nov 28-Nov 10-Dis

Akt

iviti

210 Po

, dpm

/L

0.0

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0.2

0.3

0.4

0.5

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0.6

Rajah 5. Aktiviti 210Po dalam air hujan di UKM, Bangi

S te se n1 2 3 4 5 6

Akt

iviti

210 Po

, dpm

/l

0 .0 0

0 .0 2

0 .0 4

0 .0 6

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0 .1 0

0 .1 2

0 .1 4

P e rm u k aa n P e rte n g ah a n D a sa r

210Rajah 6. Aktiviti Pb dalam air laut di Pulau Tinggi, Johor

INFLUENCE OF PRECIPITATING AGENT ON COPPER(II) OXIDE SYNTHESISED VIA PRECIPITATION METHOD

Irmawati Ramli*, Hooi Hong Lau Y.H. and Taufiq-Yap

Depar ysia, 43400 UPM Serdang, Selangor D.E., Malaysia.

tment of Chemistry, Universiti Putra Mala

Email: [email protected]

Abstract. Copper(II) oxide powders were synthesized by the precipitation of a copper nitrate solution in 1.0 M with precipitating agents such as ammonium hydroxide, ammonium carbonate and sodium carbonate, respectively, in 1.5 M. By using sodium carbonate, the crystallites of copper(II) oxide formed were smaller than by using the others two. On the other hand, its high surface area promotes the total amount of oxygen removed.

bstrak. Serbuk kuprum(II) oksida telah disintesisA kan melalui pemendakan daripada 1.0 M larutan kuprum nitrat dengan

ng lain. Di samping itu, luas permukaan hablurnya menggalakkan jumlah pelepasan oksigen ng tinggi.

(II) oxide, pH, precipitation, precipitating agent

ntrodu

tration of 1.0 M was placed in a round bottom flask under g. The solution was then titrated with 1.5 M of ammonium hydroxide, (NH4)OH in

ped at pH 3.0. The solid was filtered and was let ntaining silica gel. The solid phase obtained after drying was weighed and

d were labelled as AHpre, where AH = 1.5 M of ammonium hydroxide; pre

pitated from different precipitating agents. he diffractograms are similar to each other and show the presence of well crystallised copper

1.5 M agen pemendakan seperti ammonium hidroksida, ammonium karbonat dan sodium karbonat, masing-masing. Dengan menggunakan sodium karbonat, hablur kuprum(II) oksida yang terbentuk adalah lebih kecil daripada hablur yang terhasil daripada agen pemendakan yaya Keywords: copper I ction Copper(II) oxide, CuO occurs in nature as the black minerals. It crystallizes in a monoclinic structure. In mineralogy, copper(II) oxide is known as tenorite. Its molecular weight is 79.54 g mol-1 and melts at 1603 K. Sometimes, copper(II) oxide is also known as cupric oxide [1]. One of the largest commercial applications of copper(II) oxide is in the production of compounds for wood preservation. Copper(II) oxide is also used extensively as a feed additive and as a pigment in glass, ceramic and porcelain enamels. In many catalytic reactions, it is a main component in various catalysts [1]. Copper(II) oxide catalysts have been widely used in many chemical reactions that involve hydrogen as a reactant or a product. For example methanol synthesis from carbon monoxide or carbon dioxide [2], the water-gas shift reaction and methanol steam reforming [3]. Besides, copper(II) oxide is also used as catalyst in carbon monoxide oxidation [4] and propene oxidation [5]. In this work, influence of precipitating agent on the physicochemical properties of CuO was studied. Experimental

0 mL of copper nitrate solution in concen5moderate stirrin

rop wise manner. The precipitation process was stopdto dry in a desiccator co

round. The solids obtaineg= precursor. The whole procedure was repeated. This time, 1.5 M of sodium carbonate, Na2CO3 and ammonium carbonate, (NH4)2CO3 were used as the precipitating agent, respectively. The precursors obtained from the process were labelled as SCpre, and ACpre where SC = 1.5 M of sodium carbonate and AC = 1.5 M of ammonium carbonate. All of the precursors were calcined in air at 623 K for 5 hours. The calcined samples were labelled as AH, SC and AC. The calcined samples were characterised by using Shimadzu Diffractometer model XRD-6000 for X-ray diffraction (XRD) analyses, ThermoFinnigan Sorptomatic 1990 for B.E.T. surface area measurements, JEOL scanning electron microscope, model JSM-6400 for morphological studies and ThermoFinnigan TPDRO 1100 for temperature-programmed reduction in hydrogen (H2-TPR). Results and Discussion Figure 1 shows the XRD patterns of the precursors preciT

ase (JCPDS File No. 450594). All the precursors have monoclinic structure and is agreement with Guillou et al. [6]. The peaks of Cu2(OH)3NO3 are present at 2θ = 12.6, 21.4, 25.6,

per(II) oxide phase (JCPDS File No. 5-0661). The obtained CuO owders presented the main peaks at 2θ = 35.5, 38.7 and 48.7˚. These three peaks correspond to

hydroxyl nitrate phin31.8, 33.5, 36.2 and 58.1˚. The overall reaction of the precipitation process was the mixture solution of copper nitrate and precipitating agent yielded the copper hydroxyl nitrate solid and ammonium nitrate. Figure 2 indicates the XRD patterns of calcined samples. Calcination at 623 K transformed the copper hydroxyl nitrate into copp111), (111) and )022( p( lanes. Carbonate anion from sodium carbonate promotes the formation of

1.5 M of different tions (NH4OH, (NH4)2CO3 and Na2CO3). A single peak at maximum observed in sample AH, corresponding to activation energy of 97.8 kJ mol-

oved is 6.7 x 1021 atom g-1 for AH and 6.9 x 021 atom g-1 for AC copper(II) oxide. For SC, the total amount of hydrogen consumed is 7.8 x 1021 om g-1. A correlation is observed between the total amount of oxygen atom removed and the BET rface area of copper(II) oxide produced. As shown in Figure 4.34, there is an increment of total

mount of oxygen atom removed when the surface area of copper(II) oxide increased. This happening ay be due to a wide exposure of sample surface to the hydrogen when surface area of sample creased.

smaller crystallites in granular morphology. Figure 3(a) shows the morphology of AH in tabular plate-like structure with indented contours. Figure 3(b) illustrates the morphology of AC in platelet morphology. Figure 3(c) shows the morphology of SC is in dispersive granular morphology. The dispersive granular copper(II) oxide is suggested to be a factor that caused the surface area of SC (7.7 m2 g-1) higher than AC (3.6 m2 g-1) and AH (2.3 m2 g-1). Figure 4 shows the hydrogen TPR profiles of he copper(II) oxide prepared from 1.0 M of copper nitrate solution witht

precipitating agent soluemperature of 585 K wast

1. Three reduction peaks at maximum temperature of 474, 490 and 528 K were observed in sample AC, with corresponding activation energies of 79.3, 81.9 and 88.3 kJ mol-1. For sample SC, only single peak was found at 498 K with calculated reduction activation energy of 83.3 kJ mol-1. The total amount of oxygen removed being determined by quantification of the H2 consumed and is shown by integrating the area under the TPR profile. The amount of oxygen removed obtained by hydrogen

PR are shown in Table 1. The total oxygen atom remT1atsuamin

0

10000

20000

30000

40000

10

Figure 1. XRD patterns of uncalcined samples. Figure 2. XRD patterns of calcined samples.

20 30 40 50 60

SCpre

ACpre

AHpre

Cu2(OH)3NO3

JCPDS No. 450594

2θ (degree)

Inte

nsity

(a.u

.)

0

5000

10000

15000

10 20 30 40 50 60

CuO

SC

AC

AH

JCPDS No. 5-0661

2θ (degree)

Inte

nsity

(a.u

.)

(a) (b) (c)

Figure 3. SEM micrograph of (a) AH (b) AC and (c) SC.

Table 1. H2-TPR data of copper(II) oxide.

Samples Peak Tmax (K) Reduction activation energy, Er (kJ mol-1)

Total amount of

oxygen removed (mol g-1)

Total amount of

oxygen removed (atom g-1)

350 400 450 500 550 600 650 700

498

5

Figure 4. H2-TPR profiles of copper(II) oxide.

AH 1 585 97.8 1.1 x 10-2 6.7 x 1021

AC 1 474 79.3 5.0 x 10-3 3.0 x 1021 2 490 81.9 4.6 x 10-3 2.7 x 1021 3 528 88.3 2.0 x 10-3 1.2 x 1021

Total 1.2 x 10-2 6.9 x 1021

SC 1 498 83.3 1.3 x 10-2 7.8 x 1021

Conclusions The phase structure of copper(II) oxide and its precursor was not influenced by the variation of precipitating agents. Nevertheless, the variation in precipitating agent in preparation of copper(II) oxide which affected the surface area and morphology of copper(II) oxide have greatly affected the total amount of oxygen removed from copper(II) oxide. Results showed that higher surface area value of CuO increased the removable of oxygen species in reduction reaction by hydrogen. Acknowledgement Financial assistance from Malaysian Ministry of Science, Technology and Innovation is gratefully acknowledged. References 1. Richardson, H. W. (2003) "Ullmann's Encyclopedia of Industrial Chemistry", Germany: Wiley-VCH. 2. Kung, H. H. (1989) "Transition Metal Oxides: Surface Chemistry and Catalysis", New York: Elsevier. 3. Ridler, D. E. and Twigg, M. V. (1989) "Catalysis Handbook", ed. Twigg, M. V., Frome, England: Wolfe

ublishing Ltd. P

28

490474

585

SC

AC

AH

Temperature (K)

Rat

e of

Hyd

roge

n C

onsu

mpt

ion

4. Huang, T.-J. and Tsai, D.-H. (2003) "CO Oxidation Behavior of Copper and Copper Oxides" Catalysis Letters 87. 173-178. Lin, M. M. (2001) "Selective oxidation of propane to acrylic acid with molecular oxygen" Applied Catalysis A: General 207. 1-16.

6. Guillou, N., Louër, M. and Louër, D. (1994) "An X-ray and neutron powder diffraction study of a new polymorphic phase of copper hydroxide nitrate" Journal of Solid State Chemistry 109. 307-304.

5.

PHASE BOUNDARY HETEROGENEOUS TIO2/ZRO2 CATALYST FOR EPOXIDATION

Izan Izwan Misnon, Hadi Nur and Halimaton Hamdan

Ibnu Sina Institute for Fundamental Science studies, Universiti Teknologi Malaysia, Skudai, Johor 81000 Malaysia.

Abstract - A heterogeneous oxidation catalyst was prepared by fluorination of TiO2 impregnated

es with ammonium hexafluorosilicate [(NH4)2SiF6] followed by alkylsilylation of n-ctadecyltrichlorosilane (OTS). Enhanced catalytic activity of the system was observed in a liquid

cat tivity of the modified TiO2/ZrO2 is attributed to the modified local environment of titanium

Ke ium hexafluorosilicate, fluorination, alkylsilylation, titanium, zirconia,hydrophobicity Introduction

Heterogeneous catalyst such as titanium silicalite (TS-1) has been successfully applied in a variety of oxidation reactions, namely the selective epoxidation of olefins and diolefins, the selective

kemo trahedral Ti species in the hydrophobic framework [3].

However, in TS-1, the active sites are located in the internal framework [4] which limits its application to substrates with relatively small molecular sizes [3]. Consequently, large molecules with

ng structures are not accessible, reducing its catalytic capabilities. Due to the importance of Ti active is a need to design a system where Ti can be located in the external framework or at the

external surface which enable it to freely directly interact with every substrate. Studies have shown that extraframework tetrahedral Ti is formed when fluorides are used [5]. Other modification shows that epoxidation reaction will increase via alkylsilylation [6]. Alkylsilylation is to increase the hydrophobicity and protect Ti active sites.

In this research, zirconia will be used as the catalyst support. The epoxidation catalyst will be further modified with fluorine and enhanced with alkylsilylation, in order to create more tetrahedral Ti and increase hydrophobicity respectively. Experimental Catalysts preparation Catalyst was prepared by impregnation of raw material. 500 µmole of [Ti(PrO)4] in addition of 1g of [Zr(OH)4] was mixed with stirring until the solvent is completely dry. The sample was calcined at 500

oC for 2h at a rate of 2 oC/min in the furnace. Then, the sample was grind and labeled as TiO2/ZrO2. Double distilled water (10 mL) was mixed with [(NH4)2SiF6] to make 1M clear solution. Next, it is added to the container that contains TiO2/ZrO2. The mixture was shaken for five min before undergoing ultrasonic treatment for 10 min at 30 oC. The suspension was then collected by centrifugation at 3500 rpm for 20 min using centrifugation machine. Excess of solvent was discarded and the wet-precipitate was heated at 100 oC overnight. Then, the sample was grind and labeled as F-TiO2/ZrO2. Preparation of O-F-TiO2/ZrO2 was done by surface modification of F-TiO2/ZrO2 through alkysilylation of OTS. Toluene (10 mL) containing OTS (250 µmole) was added to the container that contain F-TiO2/ZrO2 powder (1g). The mixture was shaken for 20 minutes at room temperature. The suspension was collected by centrifugation. The yield obtained was heated at 100 oC overnight and then the prepared samples are labeled as O-F-TiO2/ZrO2.

ZrO2 particlophase epoxidation of 1-octene with aqueous hydrogen peroxide to produce 1,2-epoxyoctane. The

alytic acactive sites and increased hydrophobicity.

ywords: Epoxidation catalyst, ammon

oxidation of primary alcohol to aldehydes and secondary alcohols to ketones, the ammoximation of tones to oximes, the hydroxylation of aromatic and aliphatic compounds [1,2]. Its unique activity is stly due to the isolated te

risites, there

190 250 300 350 400 450 500

0.2 0.4 0.6

0

nm

0.8 1.

1.2 F- TiO2/ ZrO2

O-F-TiO2/ ZrO2

Tetrahedral Octahedral

Figure 1: UV-VIS diffuse reflectance spectra of TiO2/ZrO2, F-TiO2/ZrO2 and O-F-TiO2/ZrO2.

Charact Comprehensive c ations were done by X-Ray Diffraction (XRD), UV-VIS Diffuse Reflactance, SEM, EDAX and Surface Analyzer. These characterizations are done in order to confirm the surface structure of catalysts and their active sites that undergo modifications. Catalytic Measurement In this study, 1- r (50 mg) were placed in a glass tube before it was tightly closed. The glass tube was covered using aluminum foil. This was carried out in order to prevent decomposition of H O before the reaction started. The

nce of tetrahedral Ti ormed from the octahedral Ti framework during fluorination. face area of fluorinated TiO2/ZrO2 (F-TiO2/ZrO2) (21.24 m2/g) is almost similar to that

ylated O-F-TiO2/ZrO2 (19.63 m2/g) suggesting that alkylsilylation does not affect the a of the catalysts (see Table 1).

Data in Table 1 agree with the relative crystallinity results obtained by XRD as shown in Fig. 2. The major peaks tend to appear at 2Ө range of 20o to 40o. The X-ray diffractograms demonstrate that all the modified catalysts possess a similar crystalline structure with characteristic peaks at 28.2o and 31.5o, corresponding to the monoclinic phase of ZrO2. It was observed that there is no change in

erization

haracterizations of the catalysts resulted from zirconia surface modific

octene (4 mL), H2O2 (1 mL), and TiO2/ZrO2 fine sample catalyst powde

2 2 reaction was performed under stirring for 24h at room temperature. The resulting product was characterized using GC. The same procedure was repeated with other catalysts. Results and Discussion Figure 1 shows UV-Vis Diffuse Reflectance spectra of TiO2/ZrO2, F-TiO2/ZrO2 and O-F-TiO2/ZrO2. The band in the range of 200–240 nm is attributed to a charge-transfer of the tetrahedral Ti sites between O2- and the central Ti(IV) atoms, while octahedral Ti was reported to appear at around 260–330 nm. It shows that, for samples containing fluor (F-TiO2/ZrO2 and O-F-TiO2/ZrO2), only single high intense band at around 208 nm can be observed.

This band is attributable to Ti in the tetrahedral structure. The decrease in intensity in the

ange of 260-330 nm, which correspond to the octahedral Ti, indicates the occurrerstructure; transf

The surof alkylsilsurface are

the crystallinity of the modified ZrO2 after impregnation of TiO2 and modification with (NH4)2SiF6 and OTS. The highly stable properties of ZrO2 surface contributes to the unaltered surface area.

and carbon (C) in O-F-TiO /ZrO are 55.4 wt% and 19.5 wt% respectively, in which carbon originates from alkylsilyl group

mount of titanium (Ti) and silicon (Si) show only 4.0 wt% and 2.0 wt%, respectively on the surface of the catalyst. Fluorine (F) and chlorine (Cl) only takes part

As shown in Fig. 3, fluorination and alkylsilylation onto the surface of TiO2/ZrO2 increases y be explained in terms of the local environment of Ti

active site. It is generally accepted that isolated Ti in tetrahedral form are considered the most active species in epoxidation reaction. Based on these findings, the effect of fluorination on increasing the epoxidation activity of F-TiO2/ZrO2 and O-F-TiO2/ZrO2 can be explained by the presence of isolated Ti in tetrahedral form (see Fig. 1). As shown in Fig. 4, tetrahedral Ti reacted with 1-octene to give 1,2-epoxyoctane.

ace Area (m2/g)

Table 1: Summary of the total surface area obtained for all samples.

Modified Catalyst Specific Surf

TiO2/ZrO2 N/A

F-TiO2/ZrO2 21.24

O-F-TiO2/ZrO2 19.63

Figure 2: X-ray diffractograms pattern of unmodified ZrO2 support and modified TiO2/ZrO2, F-

TiO2/ZrO2 and O-F-TiO2/ZrO2.

The EDAX analysis indicates that the amount of zirconium (Zr) 2 2

attached on the surface of the sample. The a

ca. 1.0 wt% and 1.8 wt% respectively. This result shows that the amount of F in O-F-TiO2/ZrO2 (ca. 1.0 wt%) is very much lower compared to the amount of [(NH4)2SiF6] added during the fluorination process (ca. 28%).

SEM micrographs of TiO2/ZrO2, F-TiO2/ZrO2 and O-F-TiO2/ZrO2 samples revealed that there is no significant difference in morphology and the particle size among the samples. This suggests that fluorination and alkylsilylation processes did not change the morphology and particle size of ZrO2. This is supported by the fact that the structure of ZrO2 is still maintained after introduction of fluorine and alkylsilyl groups (see Fig. 2). Furthermore, the samples also showed the irregularity in their morphology in multi particle size distribution.

their epoxidation activity. This phenomenon ma

10 20 30 40 50 60 70

ZrO2

TiO /ZrO2 2

O-F-TiO2/ZrO2

F-TiO2/ZrO2

2-theta

igure 3: Column chart of epoxidation-catalyzed reaction.

F

O

T i O

H 2 O 2

O S i

F F F F FF

A considerable increase in the epoxide yield was observed when the surface of F- TiO2/ZrO2 was alkylsilylated with OTS (O-F-TiO2/ZrO2) (see Fig. 3). This can be explained

on the basis of an increase in the hydrophobicity of F-TiO2/ZrO2 by alkylsilylation. When the substrates interact with the active sites on the Ti active sites, the H2O2 releases water as a side product. If this happens, Ti active sites will be poisoned by water molecules and it might reduce the catalytic activity. The long hydrophobic carbon chains of alkylsilyl groups would prevent the water to interact with Ti active sites.

onclusion

catalytic activity

10,37

71,8

155,35

0

50

100

150

200

ZrO2/TiO2 F-ZrO2/TiO2 O-F-ZrO2/TiO2

sample

yeild

(µm

ole)

Figure 4: Proposed model of F-TiO2/ZrO2 as catalyst for transformation of 1-octene to 1,2-epoxyoctane.

C The results from the study indicate that TiO2/ZrO2, F-TiO2/ZrO2, and O-F-TiO2/ZrO2 are active atalyts in the epoxidation of 1-octene. Activity of the catalysts is due to the presence of Ti active

talytic performance is brought about by fluorination and lkylsilylation processes of TiO /ZrO . We have demonstrated that fluorination can change the

csites on their surface. The increase in caa 2 2coordination of Ti active sites from octahedral to tetrahedral and also increase the hydrophobicity of

the catalyst. Alkylsilylation on the other side has absolutely increased hydrophobicity of the catalyst by preventing the Ti active sites from being poisoned by water molecules. The catalytic activity of O-F-TiO2/ZrO2 increase significantly in the epoxidation of 1-octene with aqueous H2O2 due to two pro

efe

. Hamilton, D., (1973). “Technology, Man and the Environment”, London, Faber and Faber Ltd.,

2. Capel-Sanchez, M.C., Cam pregnation treatments atalysts and their r alkene epoxidation with hy e”, Applied

s A: Gen (1), 69-77. 3. , Wan . and Li (2 solvent on the propylene epoxidation

er TS-1 cata t”, Cataly is Today -95, 54 erego, C. et (2001). oducti itanium containing molecular sieve and their application

sis”, A ied Ca sis A: G l, 221(1 -72. 5 al., (1993). “Titaniu MFI-Ty eolites: A Characterization ANES,

74, 49Ti 17O MAS NMR Spectroscopy and H sorption”, d State , 102(2) 491.

6. Hadi Nur, Ikeda, S. and Ohtani, B., (2001). “Phase Boundary Catal Alkene Ep on with queous H Pero e Using iphilic Particles Loaded with Tit

, 20

perties. The first property is the presence of tetrahedral Ti active sites and second, the hydrophobic character of the catalyst. Based on its properties, fluorination and alkylsilylation of impregnated Ti active site on the surface of a support is a promising technique for the enhancement of the catalytic activity in epoxidation of alkenes with aqueous H2O2. R rences 1

69-72. pos-Martin, J.M. and Fierro, J.L.G., (2003). “Im

of TS-1 c elevance in drogen peroxidCatalysiLiu, X.

eral, 246., Guog, X

lys, X

s, G.,, 93

004). “Effect of 05-509. ov

. Pin cataly

al., ppl

“Prtaly

on of tenera -2), 63

. Lopez, A. et m in pe Z by XEXAFS, IR, and and 2O Ad J. SoliChem. , 480-

ysis of oxidatianium Oxide”, A ydrogen xid Amph Zeolite

J. Catal. 4, 402-408.

PRODUCTION OF WATER SOLUBLE AND LOW MOLECULAR WEIGHT CHITOOLIGOSACCHARIDES USING COMMERCIAL

MIXED-GLUCANASE FROM ASPERGILLUS ACULEATUS

Lee Lih Fen1, Mohd Yusof Maskat1, Rosli Md IIlias2 and Osman Hassan1*

1 School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM-Bangi, Malaysia

2 Department of Bioprocess Engineering, Faculty of Chemical Engineering and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Malaysia

*Correspondence: [email protected] Abstract. Degradation of chitinous waste by microorganisms usually proceeded through a series of low yielding but complementary enzymes in producing breakdown of chitinous material. Viscozyme® L, a commercial carbohydrase from Aspergillus aculeatus, containing a mixture of arabanase, cellulase, hemicellulase, xylanase and β-glucanase, was chosen as a model for low-yielding chitosanase acting on a chitinous material from shrimp waste. The enzymatic hydrolysis was optimised using a statistical modelling, whereby the application of 50% (w/w) of enzyme on 4% (w/v) chitosan will optimally hydrolyse the chitinous material at pH 4.52 and temperature of 54.2°C. The products obtained from the hydrolysis can be easily solubilised in cold-water [up to 10% (w/v)] to

ive clear, brownish and low-viscosity solution. Results from HPLC analys indicated hat the chitooligosaccharides consisted of DP 1-5. In conc sion, the mixed glucanases enzyme is a workable e from chitinous material.

, commercial glucanase, chitinase, chitooligosaccharide. Introduction Chitosan is a biopolymer of polysaccharide derived from chitin found in the shell of crustacean animal (

me L is a commercial enzyme containing a mixture of arabanase, cellulase, hemicellulase, xylanase and β–glucanase. Although Viscozyme® L is not the specific chitosanase, it was found to be able to hydrolyse chitosan [5]. Therefore, chitooligosaccharide can be produced at lower cost using Viscozyme® L and coupled with optimized reaction conditions. Experimental Materials Shrimp

g is tlu

nzyme to model the production of water soluble and low molecular weight chitooligosaccharides

Keywords: Chitosan

shrimp and crab) and cell wall of fungi (mushroom). In food industry, chitosan has been used as dietary fiber, anti-microbial agent [1] and coating film of fruit and vegetable [2]. Water insoluble chitosan can be degraded enzymically by chitosanase (E.C.3.2.1.132) or chitinase (E.C.3.2.1.14) to produce water soluble of oligomer or monomer of chitosan that is more suitable for human consumption and absorption. Chitosan oligomer has been developed as prebiotic [3], which enhances the growth of useful probiotics in human colon, while chitosan monomer, glucosamine, has been used as treatment for osteoarthritis [4]. However, the application of the purified and specific chitosanase in producing chitosan hydrolysates has been prevented by the scarcity and high cost of chitosanase enzymes.

Viscozy ®

chitosan (ChitoChem Sdn. Bhd., Malaysia) was ground and sieved to 115 Mesh. The crude carbohydrase mixture of Aspergillus aculeatus, named Viscozyme® L was supplied from Novozyme (Germany). The dyeing agent of Remazol Brilliant Blue ® (RBB) was purchased from Sigma (USA). Acid acetic solution (99.8%) (Hamburg Chemicals, Germany), sodium acetate trihydrate and Sodium hydroxide (Merck, Germany) were used in colloidal chitosan preparation and as pH buffer in chitosan

hydrolysis. Acetonitrile (Merck, Germany), ammonium hydroxide (R&M, UK) and deionised water were utilised as mobile phase in HPLC for chitooligosaccharides determination.

Filter paper with 20/25 µm pore size (Advantec, No. 1, Japan), polyethersulfone (PES) Ultrafiltration (UF) membranes (Vivascience, Vivaflow 50, Germany) with 10 kDa molecular weight cut-off, and methanol (Hamburg, Germany) were used in purification of chitosan hydrolysis products to be subjected for characterizations.

Procedures Colloidal chitosan was prepared and dyed with RBB according to the method of Lee et al. [5] prior to study the model of its hydrolysis by Viscozyme® L. The model study was conducted in micro-scale for screening the soluble products of hydrolysis spectrophotometrically at 595 nm. The statistical analysis and optimization of Viscozyme® L reaction was conducted with central composite design (CCD) of response surface methodology (RSM), employing a statistical package Design-Expert version 6.0.10 (Stat-Ease Inc., Minneapolis, USA). The recovery of chitooligosaccharides was done according to the optimized parameters, but using the original non-dyed chitosan powder as substrate. The chitosan hydrolysates were purified before characterization. Preparation of Colloidal Chitosan.

hitosan powder (10g) was dissolved in 0.3 M acetic asid [1:25 (v/v)] at room temperature for 30 min before being neutralized to pH by 0.3 M NaOH. After neutralization, the colloidal chitosan was wash thoroughly by distilled water until the pH became 7. The washed colloidal chitosan was filtered and dried to approximately 92% moisture content before dyeing. Dyeing of Colloidal Chitosan. The colloidal chitosan was suspended at a ratio of 10 to 1 (w/v) in 1% (w/v) RBB solution. The mixture was boiled for 60 min with gentle stirring. Then, the excess dye solution was drained, and the bonding of dye to colloidal chitosan was fixed by boiling the coloured material in 1.5% sodium dichromate and 1.5% potassium sodium tartarate tetrahydrate for 10 min. The dyed colloidal chitosan was washed thoroughly with boiling distilled water until the washing solution became colourless. The dyed chitosan is dried and finally ground to 115 mesh for subsequent study. Optimization of Viscozyme® L Hydrolysis. The RBB-dyed chitosan powder samples were suspended 4% (w/v) in 1 ml of 0.2 M acetate buffer in 1.5 ml micro-tubes. After equilibration at desired temperature for 10 min, 50% w/w Viscozyme® L was added into the solution to initiate hydrolysis. The enzyme activity was terminated and precipitated by adding 0.5 ml of 2 N NaOH. The mixtures were centrifuged (6400 rpm, 5 min) and the supernatants were transferred to a 96-well microplate (375 ml well, 1 cm height). The absorbance of supernatants was read spectrophotometrically at 595 nm, by using a 96-well microplate reader (VersaMax, Molecular Devices Inc., USA). Blanks were prepared similarly (3 replicates) but without the addition of enzyme. One unit of Viscozyme® L was defined as the amount of enzyme that produced an increase of 0.01 in the absorbance. Experimental Design and Statistical Analysis. Based on the first-order model of 2-level full fac l design experiment carried out previously (data not shown), pH perature were found to be the main factors in controlling the enzyme activity. Therefore, the l design of a

tral composite design (CCD) of response surface methodology (RSM). The CCD onsisted of 4 fractions of factorial and axial points, respectively, and 5 centre points (Table 1). The

C

9

toria and tem

optimum regions observed were used for subsequent second-order moderotatable cenc

center point of pH was 4.50 and temperature was 55.0oC. Whereas substrate concentration was fixed the value of Km determined by Lineweaver-Burk Method for Viscozyme® L acivity in

preliminary study and the initial viscosity of the original chitosan gel used was found maximum at 4% (w/v). Besides, enzyme concentration was fixed at 50% (w/w), which was the maximum point in the

ren ym ivit co of its lower co re

at 4% (w/v) as

linear t d of enz e act y and nsidering st of application. The sponse encountered in this experimental design is Viscozyme® L activity and was expressed as U/min. Initially, the polynomial of the second-order model fitted to the response was giving an equation of the form:

Y = β0 + β1X1 + β2X2 +β1

2X12 + β2

2X22 + β1β2X1X2 (1)

here X1 and X2 represented the levels of factors according to Table 1, and β0, β1 and β2 represented

coefficient estimates with β0 having the role of a scaling constant. Recovery of Chitooligosaccharides

drolysis was performed again based on the optimized parameters, but using the non-dyed hitosan powder as substate. The hydrolysis was carried out for 24 hours. The hydrolysate was filtered

min, tant was filtered again through an

high mt was concentrated to 1/5 volume by using a vacuum rotary evaporator

0o

was pof mo (v/v). After storage at -20 C for 48 hours, the precipitated chitooligosaccharides

cvacuuevapo and washed by ethanol and acetone before

ing Chara

Both dried disk to determine its degree of deacetylation (DD) by Fourier Transform Infrared (FTIR) spectroscopic [7]. The spectra of chitosan samples were obtained using an FTIR spectrometer (Perkin-Elmer, GX, USA).

analyzIntelli Plus Autosampler (USA) and Alltech Prevail

comb e. The flow rate was maintained at 1.0 ml/min. Injection volume of sample was 20 µl. The eluent was monitored by an evaporative light scattering detector (ELSD) (Eurosep Instruments, DDL 31, France).

the dsucro e (DP4) and maltopentaose (DP4), were used. All data

btained from HPLC were collected and analyzed using the Borwin Chromatography Software.

esults and Discussion

Optimization of Viscozyme® L Hydrolysis In the model study of a wide-spectrum enzyme application on chitinous material, the dyed chitosan

W

Chitosan hycthrough the 20/25 µm filter paper (Advantec, No. 1, Japan) after centrifugation at 10 000 rpm for 15

to remove the undegraded chitosan substrate. The supernaultrafiltration membrane, with 10 kDa molecular weight cut-off, to remove the enzyme protein and

olecular weight chitosan. The filtered supernatan

at 6 C. Chitooligosaccharide products were obtained by alcohol extraction. The concentrated sample recipitated in methanol (97%) at a ratio of 1 to 6 (v/v) to give the final methanol concentration re than 80% o

was entrifuged, washed 3-4 times again with methanol, ethanol and acetone to remove buffer salt and m-dried finally to obtain chitooligosaccharides fraction 1 (COS-1) [6]. The supernatant was rated and reprecipitated by ethanol, centrifuged

dry to obtain chitooligosaccharides fraction 2 (COS-2) [9].

cterizations

chitosan and its degraded chitooligosaccharides (mixtures of COS-1 and COS-2) powder were and pelletised into potassium bromide (KBr)

The components of water soluble and low molecular weight chitooligosaccharides were ed by high performance liquid chromatography (HPLC). An HPLC system consists of a Jasco gent HPLC Pump (PU 1580, Japan), Waters 717

Carbohydrate ES 5µ (250 mm x 4.6 mm) column were used. The mobile phase applied was a ination of 75% acetonitrile and 25% deionized water containing 0.04% ammonium hydroxid

The chitooligosaccharides concentration to be analyzed was approximately 10% (w/v). To determine egree of polymerization (DP), standard saccharides consisting of fructose, glucose (DP1), se (DP2), maltotriose (DP3), stachyos

o R

was spectrphotometrically d were shown to be

ster and more sensitive than the usual DNS determination [5]. Table 1 show ained. From the

results of the optimization method, Viscozyme® L activity (Y) obtained was about similar and fitted to the predicted results. The second-order model developed with the adjusted R2 of 0.9752 and stated below was significantly fitted well (p<0.05) by each variables as there is no significant lack of fit (p>0.05) in the model. Y (U/min) = 0.2568 + 0.0104 X1 – 0.0123 X2 -0.0948 X1

2 – 0.0479 X22 + 0.0339 X1X2 (2)

where X1 and X2 are factors presented in Table 1.

Table 1. Experimental design and results of RBB-chitosan hydrolysis by Viscozyme® L based on central composite rotatable design (n=3) [8]

Standard Variables

chosen as the substrate of hydrolysis. The soluble hydrolysates were determined at 595 nm. The substrate and the analytical method use

faed the experimental design, observed and predicted results obt

Order Coded Actual *Response Y:

Viscozyme® L activity (U/min)

X1 X2 pH Temperature (oC) Actual Predicted

1 -1 -1 4.00 50.0 0.143 0.150 2 1 -1 5.00 50.0 0.105 0.103 3 -1 1 4.00 60.0 0.047 0.058 4 1 1 5.00 60.0 0.144 0.146 5 -1.414 0 3.79 55.0 0.063 0.053 6 1.414 0 5.21 55.0 0.080 0.082 7 0 -1.414 4.50 47.9 0.180 0.178 8 0 1.414 4.50 62.1 0.150 0.144 9 0 0 4.50 55.0 0.264 0.257 10 0 0 4.50 55.0 0.245 0.257 11 0 0 4.50 55.0 0.273 0.257 12 0 0 4.50 55.0 0.257 0.257 13 0 0 4.50 55.0 0.243 0.257

* Viscozyme® L activity = Increase of 0.01 in the absorbance (595 nm) per min

Table 2. Analysis of Varians for Viscozyme® L activity [8]

Sum of Squares DF Mean Square F Value Prob > Source F Model X1X2X1

2 X2

2 X1X2Residu

0.2292 0.0026 0.0036 0.1876 0.0479 0.0138

5 1 1 1 1 1

0.0469 0.0026 0.0036 0.1876 0.0479 0.0138

299.6 16.42 23.24 1199 306.0 88.21

< 0.0001 0.0003

< 0.0001 < 0.0001 < 0.0001 < 0.0001

significant

al Lack of Fit Pure Error

Cor Total Std. Dev. Mean

0.0052 0.0010 0.0042 0.2396

0.0125

33 3

30 38

0.0002 0.0003 0.0001

R-Squared

2.330

0.9784

0.0944

not

significant

C.V. PRESS

0.1690 7.403

0.0067

Adj R-Squared Pred R-Squared Adq Precision

0.9752 0.9721 41.63

Contour plot presented in Figure 1 showed that the optimum condition for Viscozyme® L activity was at pH 4.52 and 54.2oC. Although Viscozyme® L is not a specific chitosanase, it was proven that the enzyme, under optimal reaction condition, can effectively degrade chitosan into chitooligosaccahrides. According to some published discussions, cellulase [9] and hemicellulase [10] were able to cleave β-1,4-glycosidic bond in chitosan. Hence, the reactivity of Viscozyme® L toward chitosan is not unexpected because of the presence of cellulase and hemicellulase that behave as low-yielding chitosanase.

DESIGN-EXPERT Plot

Viscozyme activityX = A: pHY = B: Temperature

0.058

0.108

0.158

0.208

0.258

Vis

cozy

me

activ

ity

4.00

4.25

4.50

4.75

5.00

50.00

52.50

55.00

57.50

60.00

A: pH

nted 1/6% w/v [Figure 2(a)]. Fraction COS-1 was the first extract from alcohol extraction, which was precipitated with final methanol concentration of more than 80% v/v, whereas, fraction COS-2 was the subsequent fraction by ethanol extraction,

ielded in the form of brownish powder. Fraction COS-1 [Figure 2(b)] collected as yellowish white ined more chitooligosaccharides with DP of more than 4 compared to fraction COS-2

igure 1(c)]. The chitooligosaccharides with DP up to 4 were more soluble in methanol, but more than 5 were less soluble [8]. Based on the studies by Cabrera & Cutsem

1], chitooligomers with DP up to 11 were soluble in 70 and 80% methanol and up to DP 8 only in 90% methanol. The precipitated fractions by 90% methanol were oligomers of DPs up to 16.

Glucosamine is soluble in water, but slightly soluble in methanol, and insoluble in ethanol

and reprecipitated by ethanol and washed by acetone. bsequently, acetate salt free chitosaccharides (COS-2) with DP up to 4 were obtained [Figure 2(c)].

B: Temperature

Figure 1. Response surface plot of the effect of pH and temperature on RBB-chitosan hydrolysis at 4%w/v substrate and 50%w/w enzyme for 6 hours.

Characterizations From FTIR analysis, the degree of deacetylation (DD) of the chitosan substrate was 70%. The chitosan hydrolysis was repeated using the optimized parameters with 4%w/v chitosan substrate, 50%w/w Viscozyme® L, pH 4.52 and 54.2oC for 24 hours. The chitooligosaccharides fraction which was recovered by alcohol extraction, was cold-water soluble (up to 10% w/v) to form clear, brownish and non-viscous solution.

According to Figure 2 (a) and (b), Viscozyme® L was capable to degrade chitosan and produce chitooligosaccharides, in the range between monomer and pentamer. Fructose and glucose

ith mw olecular weight (MW) 180.2, sucrose (342.3), maltotriose (504.4), stachyose (666.6) and maltopentaose (828.7) were used as standards for determining the degree of polymerization of chitoolisaccharides (approximately 76% DD) ranged from DP1 (179.2-221.2), DP2 (340.2-382.4), DP3 (501.6-543.6), DP4 (662.8-704.8) and DP5 (824.0-908.0), because the molecular weight of sugars are almost similar to chitomonosaccharide (glucosamine or N-acetyl-glucosamine) and chitooligosaccharides, (oligomers consisted of glucosamine: N-acetyl-glucosamine at least 7:3), and yet the cost is lower.

Each peak of the standard sugars represe

ypowder, conta[Foligomers with DP of[1

and acetone [6]. However, the solubility of chitooligosaccharides in those organic solvents will decrease as the DP value increase. After most of the higher chitooligosaccharides (DP>4) were removed as COS-1, the supernatant was dried Su

However, both of the fractions COS-1 and 2 contained very low amount of detected oligomers (20 and 30% respectively) due to the higher molecular weight chitooligosaccharides were removed during filtration prior to HPLC injection or reprecipitated by mobile phase and trapped inside the column, which caused an increase in backpressure of column, and thus remained as undetected products. The total chitooligosaccharide extracts obtained by alcohol extraction was only around 54% because of the low yielding activity of Viscozyme®L.

(a)

F

1 2 3 4 5

DP

igure

1

DP

2. HPLC

2

DP

profiles of (a) stan

3

DP

(b)

(c)

dard sugars, (b) COS-1 and (c)

4

DP

DP
DP DP DP
COS-2

Conclusions

Water soluble and low molecular weight chitooligosaccharides ranged from DP 1 to 5 can be obtained, by using a commercial mixed-glucanase from Aspergillus aculeatus, named Viscozyme® L (50%w/w) on 4%w/v chitosan hydrolysis at pH 4.52 and temperature of 54.2oC in 24 hours, but with only low yield of products. Acknowledgement This study was carried out with the financial support of National Biotechnology Directorate, MOSTI through Project 09-02-02-0006/BTK/ER/31 at Food Science Program, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia. Refereces 1. Sagoo, S., Board, R. & Roller, S. (2002) “Chitosan inhibits growth of spoilage micro-organisms

in chilled pork products” Food Microbiology 19: 175-182. 2. Devlieghere, F. Vermeulen, A. & Debevere, J. (2004) “Chitosan: antimicrobial activity,

interactions with food components and applicability as a coating on fruit and vegetables” Food Microbiol. 21: 703-714.

3. Lee, H., Park, Y., Jung, J. & Shin, W. (2002) “Food microbiology: Chitosan oligosaccharides, dp 2-8, have prebiotic effect on the Bifidobacterium bifidium dan Lactobacillus sp.” Anaerobe 8: 319-324.

El-Saharty, Y.S. & Bary, A.A. (2002) “High-performance liquid chromatographic determination of neutraceuticals, glucosamine sulphate and chitosan, in raw materials and dosage forms” Anal.Chimica Acta 462:125–131.

Lee L.F., Rosli, M.I., Kamarulzaman, K., Mohd Yusof, M. & Osman, H. (2005) “Development d screening method for low-yielding chitosanase activity using Remazol Brilliant Blue–

chitosan as substrate. Enz. Micro. Tech. (In Press.)

.F., Mohd Yusof, M. Rosli, M.I. & Osman, H. (2005) “The application of commercial partial-depolymerization of chitosan” Proceeding 9th Asean Food 0 December, OFPA17.

. Qin. C., Zhou, B., Zhang, Z., Liu, Y., Du, Y. & Xiao, L. (2004) “The physicochemical

4.

5.of rapi

6. Lee, M.-Y., Var, F., Shin-ya, Y., Kajiuchi, T. & Yang, J.-W. (1999) “Optimum conditions for the precipitation of chitosan oligomers with DP 5-7 in concentrated hydrochloric acid at low temperature” Process Biochem. 34:493-500.

7. Sabnis S. and Block, L.H. (1997). “Improved infrared spectroscopic method for the analysis of degree of N-deacetylation of chitosan” Polym. Bull 39: 67-71.

. Lee, L8mixed-glucanase in theConference. Jakarta., 8-1

9properties and antitumor activity of cellulose-treated chitosan” Food Chemistry 24: 107-115.

10. Qin. C., Du, Y., Xiao, L., Li, Z. & Gao, X. (2002) “Enzymic preparation of water-soluble chitosan and their antitumor activity” Int. J. Biol. Macromolecules 31: 111-117.

. Ca11 brera, J.C. & Cutsem, P.V. (2005) “Preparation of chitooligosaccharides with degree of polymerization higher than 6 by acid or enzymatic degradation of chitosan” Biochem.Engineering J. 25: 165-172.

PENGHASILAN SURFAKTAN TAK BERION BERASASKAN LAURIL ALKOHOL DARIPADA TERBITAN MINYAK KELAPA SAWIT

Norhafipah Mohamad*, Zarina Edris & Mohd Ambar Yarmo

ian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi, 43600 Universiti Kebangsaan Malaysia, Bangi.

Makmal Pemangkinan, Pusat Pengaj

Email: [email protected] Abstrak. Penghasilan surfaktan tidak berion jenis lauril alkohol teretoksilat (LAT) berasaskan produk lauril alkohol daripada minyak kelapa sawit berjaya dilakukan. Sintesis ini melibatkan tindak balas pengetoksilan antara gas etilena oksida (EO) dengan lauril alkohol (C12). Antara parameter yang dikaji dalam kajian ini adalah kesan perbezaan bilangan mol EO, tekanan dan suhu tindak balas. Tindak balas dilakukan menggunakan kalium hidroksida (KOH) sebagai mangkin homogen. Hasil terbentuk dianalisis menggunakan tekni

ipofilik (HLB) dan Ujian Dek HPLC, FTIR, ujian pembuihan, nilai Keseimbangan Hidrofilik-tergensi (peratus penyingkiran kotoran). Pembentukkan molekul LAT

kkan me uncak regangan C-O umpulan eter) pada jara menggunakan teknik

T-3 EO, 6.261 min untuk embuihan

ai kestabilan dan kekuatan buih yang baik. ng diperolehi berpotensi untuk kegunaan detergen dan

Abstract. Ethoxy nonionic surfactant type of ethoxylated lauryl alcohol (LAT) based on product of

were ance with KOH as a homogenous catalyst. LAT products were analyzed using FTIR, HPLC, foaming test, value of Hydrophilic-Lipophilic Balance (HLB) and detergency. Molecule of LAT was produced with look the sign of stretching peak C-O (group of ether) at 900 – 1350 cm-1 of wave number from FTIR. Characterization with HPLC showed the retention time of product at 6.201 minutes to LAT-3 EO, 6.261 minutes to LAT-5 EO and 6.260 minutes to LAT-7 EO. Generally, the ethoxylated product has a good potential to be used as detergent and industrial application. Kata kunci: Tindak balas pengetoksilan, lauril alkohol teretoksilat, etilena oksida, minyak sawit. Pengen

hatian iaitu penggunaan bahan mentah yang berasaskan bahan semulajadi seperti kelapa sawit dan sayur-sayuran seb tikan penggunaan produk berasaskan petrokimia. Ini berikutan daripada tren dunia

ntang penjimatan kos dan juga konsep yang lebih mesra alam. urfaktan diambil daripada singkatan perkataan ‘surface active agent’ yang bermaksud agen

ktif permukaan. Surfaktan meliputi kimia organik sintetik yang mana ia membantu dalam pembuihan, pemelarutan, pengemulsian, penyerakkan dan pembasuhan. Walaupun demikian, tidak kesemua surfaktan mempunyai ciri-ciri yang sama kerana ia sangat bergantung kepada struktur kimia molekul tersebut [2]. Surfaktan mempunyai 2 bahagian iaitu hidrofilik (suka air) dan hidrofobik (suka minyak).

Industri surfaktan kini semakin terus berkembang pesat di mana penggunaan surfaktan dunia terus meningkat kepada 11 million ton setiap tahun. Di samping itu penggunaan bahan pengemulsi, agen pembasah dan lain-lain lagi telah lama berkembang dalam sektor perindustrian. Surfaktan juga banyak digunakan dalam industri pemprosesan seperti industri makanan, farmaseutikal dan penjagaan

Ldapat ditunju lalui spektroskopi FTIR yang menandakan wujudnya p

k gelombang 900 – 1350 cm-1. Manakala pencirian(kHPLC menunjukkan masa penahanan produk ialah 6.201 min untuk LA

ncirian surfaktan melalui ujian pLAT-5 EO dan 6.260 min untuk LAT-7 EO. Pemempunymenunjukkan produk LAT yang diperolehi

ecara umum hasil menunjukkan produk yaSindustri.

fatty alcohol from palm oil product was produced successfully. Ethoxylation reaction was carried out between EO with lauryl alcohol (C12). Different moles ratio of EO, reaction temperature and pressure

among various parameters investigate. The reaction was perform

alan Malaysia merupakan negara pengeluar dan pengeksport terbesar minyak sawit. Sebanyak 90% minyak sawit yang dikeluarkan diguna dalam industri makanan dan industri oleokimia seperti pembuatan kosmetik, detergen dan sebagainya [1]. Disebabkan pasaran turun naik bagi bahan mentah surfaktan yang berasaskan minyak petroleum maka satu alternatif baru telah diberi per

agai menggante

Sa

diri. Surfaktan bukan sahaja penting sebagai juzuk yang aktif tetapi juga penting sebagai pengemulsi, penstabil dan pelembut fabrik. Rajah 1 menunjukkan kegunaan lemak dan minyak dunia. Pada 1990, pengeluaran surfaktan dunia mencapai sehingga 81 million ton yang mana 11.4 million ton menggunakan proses teknikal dan kimia [3].

Rajah 1. Kegunaan lemak dan minyak dunia

Industri surfaktan telah meningkat pada akhir dekad dan penggunaan bahan mentah semulaj rhatian bagi menggantikan produk yang berasaskan petrokimia seperti penghasilan gula berasaskan surfaktan seperti alkil glukosida [4]. Sebanyak 20 million ton bahan mentah semula telah diguna seluruh dunia setiap tahun seperti karbohidrat 15 % (55 % d k), glukosa, sukrosa dan bahan sorbitol (daripada penghidrogenan

lukosa) merupakan sebatian polihidroksi daripada bahan semulajadi. Sebatian-sebatian ini boleh pa had, mempunyai ekologi yang bagus, berketulenan tinggi serta kurang toksik. Oleh

kerana itu, kajian secara menyeluruh tentang penggunaannya dilakukan [3]. Lemak alkohol teretoksilat merupakan salah satu daripada kelas surfaktan tidak berion yang

penting. Tindak balas pengetoksilan lemak alkohol ini dilakukan dengan kehadiran mangkin. Mangkin aluminium alkoksida sulfat telah dikaji tentang keberkesanannya dalam tindak balas pengetoksilan. Hasil yang diperolehi adalah lebih tinggi berbanding mangkin bes. Namun demikian banyak produk sampingan yang terhasil [5]. Sehingga kini, mangkin bes seperti KOH dan NaOH banyak digunakan dalam industri [6]. Kajian tindak balas pengetoksilan telah dilakukan terhadap nonifenol oleh Santecaseria. Kajian ini mengenai kinetik nonilfenol teretoksilat dengan menggunakan mangkin KOH [6]. Selain itu, kajian tindak balas pengetoksilan juga telah dilakukan dengan menggunakan 1-dodecanol dan 4-nonilfenol sebagai reaktan. Kajian dilakukan untuk melihat keberkesanan tindak balas pada pelbagai suhu tindak balas dilakukan [7]. Formula umum bagi poliglikol eter yang terhasil daripada tindak balas pengetoksilan seperti kajian yang telah dilakukan oleh Alfonso dan rakan-rakan pada 2004 [1] adalah seperti berikut:

CH3 (CH2)m-(OCH2CH2)nOH

Eksperimen Reagen dan Kaedah a) Penyediaa

adi telah diberi pe

kimia yang dikitar aripada minyak dan lema

gdiguna tan

n mangkin Mangkin KOH dalam bentuk pallet dengan ketulenan 99.9 % daripada Aldrich Chemical digunakan. Sebanyak 1.34 g KOH dilarutkan dalam campuran 0.56 ml air suling dan 0.804 ml metanol daripada Fischer Scientific dengan ketulenan 99.99 %.

b) Bahan kimia dan reaktor

wap metanol. c) Pelarut dan bahan untuk ujian pencirian surfaktan Pelarut kalium bromida (KBr) digunakan dalam penyediaan sampel untuk analisis FTIR. Air suling dan metanol berketulenan 99% (Gred HPLC) daripada Fischer Scientific sebagai pelarut untuk HPLC. Cotton AS9 pigment/oil digunakan dalam ujian detergensi untuk menentukan peratus penyingkiran kotoran. Kaedah Tindak balas Pengetoksilan Reaktor pengetoksilan yang digunakan adalah daripada Vinci Technology dari Perancis. Reaktor ini mempunyai sistem keselamatan yang tinggi bagi mengendalikan gas EO. Secara umumnya reaktor tersebut terdiri daripada tangki EO, sistem vakum, penimbang EO, pam gas EO, reaktor(sistem pengetoksilan), pengawal suhu reaktor, sistem pembuangan gas EO dan sistem kawalan komputer seperti dalam skema reaktor dalam rajah 2.

CaCO3 (kalsium karbonat) daripada Fluka sebagai peneutral dalam bentuk serbuk dilarutkan dengan air suling, lauril alkohol berketulenan 99 % daripada Cognis Oleochemical sebagai bahan hidrofobik, gas etilena oksida (EO) daripada Fluka sebagai bahan hidrofilik dengan ketulenan 99% dan cecair nitrogen daripada Taylor Wharton berfungsi sebagai pemerangkap atau pemegun

V-1

V-2

Tangki EO

P-1 P-2 P-3P-2

Pam

P-4

P-3

P-5

P-3

V-3

P-7

P-3

V-5

P-8P-7

Kebuk tindak balas

P-10

Pam vakum

P-11

GC

P-12

V-7P-12

V-8

P-13

Kebuk penyahtoksik

Gas Nitrogen

P-14

P-2

V-11

P-15P-14

P-9

V-6

P-16

Skema tindak balas pengetoksilan

P-17

komputer

Rajah 2. Skema reaktor pengetoksilan. Reaktor pengetoksilan dilengkapi dengan gas EO sebagai reaktan dan gas nitrogen sebagai gas pembawa. Gas EO akan ditukar kepada bentuk cecair melalui pam EO. Kemudian cecair EO yang terhasil akan disuntik ke dalam reaktor pengetoksilan. Rajah 3 menunjukkan reaktor pengetoksilan yang diguna dalam menghasilkan surfaktan tidak berion.

Kaedah sintesis LAT merupakan satu tindak balas pengetoksilatan iaitu antara molekul etilena oksida (EO) terhadap lauril alkohol. Sebelum itu mangkin bes iaitu g KOH dilarutkan dalam

i akan kelihatan seperti gel berwarna putih.

u sejurus EO masuk ke dalam reaktor. Pengacauan terus dilakukan sepanjang roses tindak balas. Selepas tamat tindak balas, suhu reaktor diturunkan dan gas nitrogen dilalukan

dalam reaktor bertujuan untuk menyingkirkan lebihan EO yang mungkin tidak bertindak balas.

1.34campuran 0.56 ml air dan 0.804 ml metanol. Larutan ini dimasukkan ke dalam reaktor dan dipanaskan di bawah vakum pada suhu 90°C selama 1 jam di dalam reaktor pengetoksilan. Selepas 1 jam, larutanin

Seterusnya suhu reaktor terlebih dahulu dinaikkan sehingga 100 °C. Setelah itu lauril alkohol dimasukkan ke dalam reaktor dan apabila suhu berada dalam keadaan stabil iaitu pada 70 0C, EO pula disuntik masuk melalui sistem reaktor mengikut bilangan mol yang ditetapkan. Tindak balas pengetoksilan berlakp

Rajah 3. Rajah reaktor pengetoksilan.

Pencirian

roduk yang diperolehi dianalisis menggunakan teknik FTIR jenis Perkin Elmer Model GX dan PLC jenis Agilent Technologies Siri 1100 dengan menggunakan pengesan ELSD jenis Altech

0. Selepas itu pencirian seterusnya dilakukan bagi menentukan tahap pembuihan dan estabilannya serta peratus penyingkiran kotoran dengan melakukan ujian pembuihan dan ujian etergensi.

) Ujian Pembuihan LAT

jian LAT dilakukan untuk ujian pembuihan telah dilakukan terhadap surfaktan yang iperolehi iaitu keupayaan pembuihan (foaming power) dan kestabilan pembuihan (foaming

stability). Kaedah yang digunakan ini diperolehi daripada AOTD in-house method. Kaedah ini

enggunakan silinder 500 ml yang diisi dengan larutan surfaktan (0.2 g dalam 200 ml air ternyahion).

lan pembuihan adalah diukur berdasarkan

PHModel 200kd a Ud

mLarutan dikocak menggunakan rod selama 30 kali pada kadar yang tetap. Apabila buih terbentuk, bacaan diambil bagi mengira kadar keupayaan pembuihan iaitu kemampuan surfaktan menghasilkan buih, berdasarkan persamaan :-

Keupayaan pembuihan = [(takat atas) – (takat bawah)/ Jumlah ketinggian] Manakala kestabilan pembuihan pula diukur selepas 5 minit kocakan. Kestabi

emampuan surfaktan mengekalkan tahap pembuihan dalam masa tertentu dan iak

persamaan:-

kiran kotoran

pigment/oil imasukkan ke dalam bekas untuk pencucian selama 10 minit. Akhir sekali, cotton AS9

pigment/oil dibilas sebanyak 2 kali dengan 1000 ml dan 500 ml air liat. Peratus penyingkiran kotoran dikira berdasarkan:

% penyingkiran kotoran = [(AW-BW) / (BS-BW)] x 100 AW = intensiti kecerahan selepas cucian terhadap cotton AS9 pigment/oil BW = sebelum cucian terhadap cotton AS9 pigment/oil BS = sebelum cucian dalam standard clothes Hasil dan Perbincangan Proses pengetoksilan Proses pengetoksilan lauril alkohol berjaya dijalankan pada julat suhu 100 0C - 135 0C dengan masa tindak balas selama 2 jam. Tindak balas yang berlaku adalah seperti berikut:

CH3 (CH2)11-OH + n (CH2CH2O) CH3 (CH2)11-(OCH2CH2)nOH

(Lauril alkohol) (EO) (LAT)

Kena k ke dalam aktor 0 0

n sehinnga 90 ol dimasukkan ke dalam reaktor (a). reaktor mputer adalah stabil iaitu pada 700C dan pada

a) FTIR Perubahan w ipada war roses pengetoksilan tamat menandakan wujudnya sebatian baru iaitu LAT. Produk yang terhasil dianalisis

engan menggunakan teknik FTIR. Sampel disedia dengan menggunakan teknik lazim. Kumpulan yang wujud dalam sebatian yang dikaji dapat diketahui melalui maklumat yang diperolehi

daripada spectrum FTIR. Rajah 5 menunjukkan spektrum bagi lauril alkohol dan sebatian-sebatian LAT yang diperolehi.

Kestabilan pembuihan = [(takat atas) – (takat bawah)/ Jumlah ketinggian] b) Peratus penying Dalam pencucian, % keupayaan detergen diuji dengan menggunakan spektrofotometer CM36000. Dalam eksperimen ini, detergen diuji ke atas cotton AS9 pigment/oil. Surfaktan terhasil dicairkan dengan menggunakna 100 ml air suling dan dicampur dengan 50 ppm air liat (hardness water) selama 3 minit. Selepas proses pencampuran, cotton AS9d

ikan suhu reaktor dapat dilihat secara mendadak semasa EO disuntire iaitu dari 60 C sehingga 120 C melebihi suhu yang diset pada monitor. Ini menandakan tindak balas eksotermik telah berlaku pada tindak balas pengetoksilan tersebut. Rajah 4 (i) menunjukkan profil perubahan suhu reaktor semasa tindak balas pengetoksilan berlaku dan rajah 4 (ii) pula menunjukkan graf suhu yang telah diset pada monitor.

Suhu reaktor dikawal sepenuhnya oleh komputer. Pada awalnya suhu dinaikka0C dan pada ketika suhu mencapai 50 0C lauril alkoh

ibiarkan seketika sehingga suhu yang tercatat pada kodketika ini, EO disuntik (b). Peningkatan suhu secara mendadak dapat dilihat setelah EO habis disuntik iaitu daripada suhu 60 0C dan meningkat sehingga 120 0C. Ini menandakan tindak balas eksotermik berlaku. Ini adalah kerana kereaktifan molekul EO dan aktiviti mangkin yang digunakan.

Pencirian LAT

arna dar na jernih lauril alkohol kepada warna kuning keemasan setelah p

dberfungsi

Rajah 4. Profil suhu tindak balas pengetoksilan LAT. (a) = Kemasukkan lauril alkohol. (b) = EO disuntik.

Masa tindak balas.

(c) =

Rajah 5. Spektrum FTIR bagi produk LAT dan lauril alkohol.

Spektrum FTIR bagi semua siri LAT dan lauril alkohol yang diperolehi menunjukkan wujudnya puncak ikatan O-H (i) pada jarak gelombang 2500 – 3450 cm-1 dan puncak regangan C-O (ii) pada jarak gelombang 900 – 1350 cm-1. Regangan C-O menandakan bahawa hasil yang diperolehi adalah sebatian yang mempunyai kumpulan eter.

b) HPLC Setelah itu, LAT yang diperolehi dianlisis dengan menggunakan teknik HPLC. Turus jenis Zorbax

00 SB-C18 digunakan bagi mendapatkan spektrum LAT. Pelarut yang digunakan adalah metanol gan nisbah 90:10. Sampel disuntik pada kadar 2 µl dengan kadar alir bagi teknik ini adalah

ml/min. Rajah 6 menunjukkan kromatogram HPLC bagi LAT yang diperolehi.

3dan air den1

(a) (b)

(c) (d)

Rajah 6. Kromatogram HPLC bagi sebatian lauril alkohol (a), LAT-3EO (b), LAT-5EO (c) dan LAT-7EO (d).

Peratus penukaran produk diperolehi berdasarkan teknik ini. Daripada analisis kromatogram, peratus penukaran produk bagi LAT hampir mencapai 100 % seperti yang tercatat dalam jadual 1 di bawah.

Jadual 1. Hasil analisis berdasarkan kromatogram HPLC.

Produk Bilangan mol EO

Masa penahanan (min)

Peratus penukaran produk

0 1.846 0 3 6.201 70.6

Lauril alkohol

5 6.261 97.6 tereto

7 6.260 79.8

ksilat (LAT)

c) Ujian Detergensi Ujian pencucian dilakukan terhadap LAT yang terhasil bagi menentukan peratus penyingkiran kotoran. Dalam proses ini, 3 elemen diambil kira iaitu substrat, jenis kotoran dan larutan pembersih dalam menentukan keberkesanan pencucian. Struktur kimia bagi panjang rantai kumpulan hidrofobik dan hidrofilik menentukan peratus pencucian kotoran. Panjang rantai karbon yang lurus adalah lebih baik daripada rantai karbon bercabang bagi kumpulan hidrofobik dan peningkatan panjang rantai kumpulan ini akan meningkatkan lagi keberkesanan pemindahan kotoran berminyak [8]. Manakala peningkatan kumpulan hidrofilik dalam rantai polioksietilena (POE) menunjukkan penurunan keberkesanan jerapan surfaktan ke atas suatu bahan dan ia berkaitan dengan penurunan dalam detergensi, contohnya dalam ujian detergensi kain kapas pada suhu 30 0C oleh POE nonilfenol dalam air suling menurun dengan peningkatan kumpulan EO daripada 9 kepada 20 [9]. Rajah 7 menunjukkan peratus penyingkiran kotoran LAT (surfaktan tidak berion) yang diperolehi.

Rajah 7. Peratus penyingkiran kotoran bagi surfaktan tidak berion. Peratus penyingkiran kotoran bagi LAT-5 EO adalah lebih tinggi berbanding LAT-3 EO dan LAT-7 EO. Ini menunjukkan panjang rantai EO iaitu kumpulan hidrofilik mempengaruhi peratus penyingkiran kotoran, iaitu semakin panjang EO maka semakin rendah peratus penyingkiran kotoran. Namun demikian, rantai EO terlalu pendek juga mempengaruhi peratus pencucian. Oleh sebab itu, LAT dengan 5 mol EO adalah amat sesuai digunakan dalam detergen berdasarkan ujian detergensi yang dilakukan.

0

Surfaktan tidak berion

3 EO 5 EO 7 EO

22 - 23 - 24 - 25 - 26 - 27 - 28 - 29 - 30 -

(%)

kira

n ko

tora

n P

enyi

ng

d) Ujian Pembuihan Ujian pembuihan bergantung kepada panjang rantai alkil, darjah pengetoksilan dan nisbah surfaktan yang hadir. Peningkatan darjah pengetoksilan akan menghasilkan surfaktan yang lebih larut air [10]. Semasa pembuihan, permukaan udara-air terbentuk. Secara amnya ia akan menghasilkan luas permukaan yang tinggi bagi jerapan surfaktan yang tidak lengkap. Luas permukaan akan menurun dengan masa dan ini merupakan peningkatan jerapan surfaktan. Ujian pembuihan menentukan tahap keupayaan buih dan kestabilan buih yang terhasil. Rajah 8 menunjukkan keupayaan dan kestabilan pembuihan bagi LAT yang diperolehi.

0

20

40

60

80

100

120

(ml)

3 EO 5 EO 7 EOLauril alkohol teretoksilat

Ket

ingg

ian

buih

0 minit 5 minit

a peningkatan bilangan kumpulan EO dalam surfaktan tidak empengaruhi peningkatan dalam keupayaan pembuihan dan kestabilan pembuihan.

) Nilai Keseimbangan Hidrofilik-Lipofilik (HLB)

Rajah 8. Keupayaan dan kestabilan pembuihan bagi semua siri LAT.

Keupayaan pembuihan LAT-7 EO yang terhasil adalah lebih tinggi berbanding LAT-3 EO dan LAT-5 EO. Namun, LAT-5 EO memberikan kestabilan pembuihan yang lebih baik berbanding LAT-3 EO dan LAT-7 EO. Secara amnym e Produk LAT yang diperolehi dihitung nilai HLBnya berdasarkan persamaan (i). Jadual 2 di bawah menunjukkan peratus hasilan lauril alkohol teretoksilat (LAT) yang diperolehi. Berdasarkan jadual 3, nilai HLB bagi produk LAT yang diperolehi menandakan ia mempunyai ciri-ciri sebagai agen pengemulsi yang sesuai digunakan dalam penghasilan detergen.

HLB = MlMh +

xMh20 Persamaan (i)

Mh = berat bahagian hidrofilik

Ml = berat bahagian hidrofobik

Jadual 2. LAT yang terhasil dengan berat molekul, nilai HLB dan peratus hasilannya.

Produk Berat molekul Nilai HLB % Hasilan LAT + 3 EO 318 8.30 91.52 % LAT + 5 EO 406 10.84 88.96 % LAT + 7 EO 494 12.47 99.63 %

Jadual 3. Ciri-ciri surfaktan berdasarkan nilai HLBnya.

Nilai HLB Ciri-ciri surfaktan / Potensi kegunaan

3 – 6 air dalam pengemulsi minyak

7 – 9 agen pembasah

8 – 15 minyak dalam pengemulsi air

12 – 15 bersifat detergen

15 – 18 bersifat keterlarutan Kesimpulan Bahan kimia berasaskan bahan semulajadi daripada minyak sawit digunakan iaitu lauril alkohol. Ini berikutan banyak kelebihan yang boleh diperolehi daripada bahan semulajadi ini. Selain daripada senang diperolehi dan murah, penggunaannya juga akan menghasilkan produk yang tidak toksik dan mudah terbiodegradasi.

Hasil analisis menunjukkan bahawa LAT telah berjaya dihasilkan berdasarkan teknik FTIR dan HPLC. Teknik FTIR menunjukkan wujudnya satu sebatian baru selepas tindak balas pengetoksilan dilakukan terhadap lauril alkohol. Terdapat puncak ikatan O-H pada jarak gelombang 2500 – 3450 cm-1 dan puncak regangan C-O pada jarak gelombang 900 – 1350 cm-1. Regangan C-O

enandakan hasil yang diperolehi adalah sebatian yang mempunyai kumpulan eter. Sebagaimana yang diketahui, melalui tindak balas pengetoksilan lemak alkohol akan menghasilkan sebatian poliglikol eter.

Manakala melalui teknik HPLC menunjukkan peratus penukaran produk yang tinggi iaitu menghamp urfaktan dilakukan ke atas semua siri produk LAT, dapat disimpulkan bahawa produk LAT-5 EO adalah lebih sesuai untuk kegunaan industri dan detergen. Ini adalah berdasarkan pada nilai HLBnya iaitu 10.84 dan ujian detergensi yang dilakukan menunjukkan peratus pencucian bagi LAT-5 EO adalah tinggi daripada LAT-3 EO dan LAT-7 EO dan mempunyai keupayaan pembuihan yang rendah berbanding

m

iri 100 % bagi produk-produk LAT ini. Setelah pelbagai pencirian s

LAT yang lain. Sebagaimana yang diketahui pembuihan yang tinggi tidak menentukan detergen yang baik. LAT-5 EO adalah lebih berpotensi dalam penggunaan detergen berbanding produk LAT yang lain berdasarkan ujian-ujian yang dilakukan ke atasnya. Penghargaan

Setinggi-tinggi ucapan terima kasih diucapkan kepada pihak MOSTE ‘Ministry of Science

Technology and Innovation of Malaysia’ di atas geran penyelidikkan IRPA 09-02-02-0033 SR0004/05-03. Selain itu, jutaan terima kasih juga diucapkan kepada Jabatan Kimia, Pusat Sains

Kimia dan Teknologi Makanan, Fakulti sains dan Teknol sia (UKM). Rujukan 1. Alfonso, E. S., Citterio. A., Ramis-Ramos, G., Righetti, P. G. & Sebastiano, R. (2004)

“Separation of Fatty Alcohol Polyethoxylates by Capillary Electrophoresis Through Easy Electroosmotic Flow Control with a Queternary Diammonium Salt” Journal of Chromatography A 1053. 235-239.

r, S. (2004) Surfactants. . Baumann, H. & Biermann, H. (1992) “Oleochemical Surfactants Today” The International

Journal of Oil Palm Research & Development 4. Johansson, I. & Svensson, M. (2001) “Surfactants Based on Fatty Acids and Other Natural

Hydrophobes” Current Opinion in Colloid & Interfa ence 6. 178-1885. Bruni, S., DiSerio, M., Gobetto, R., Iengo, P. & Sant 996) “Ethoxylation of Fatty

Alcohols Promoted by an Al ium Alkoxide Sulphate Catalyst” Journal of Molecular Catalysis A: Chemical 112. 235-251.

6. Massey, N. (2005) “Predicting The Distribution of Ethoxylation Homologues with a Process tation, Inc. 1-9.

. DiSerio M., Santacesaria E. & Tesser R. (1995) “Role of Ethylene Oxide Solubility in the

Foam urfaces” Physicohhem. Eng. Aspects 263. 226-23

(2005) “Surfactant Parameter Effects on Cleaning Efficiency” Research Triangle Institute. 405-414.

oap and Detergents”, C & EN Northeast News Bureau.

ogi, Universiti Kebangsaan Malay

2. Ishikawa, Y., Modler, R. & Muelle3

6 (1).

ce Sci . acesaria E. (1

umin

Simulator” Chems7

Ethoxylation Processes” Catalysis Today 24. 23-28. 8. Rosen, M. H. (1978) “Surfactants and Interfacial Phenomena” A. Wiley Interscience

Publication. 272-291. 9. Schwuger, A. M. (1971) Journal Am Oil Chemistry Society 48. 566. 10. Sawicki, G. C. (2005) “Impact of Surfactant Composition and Surfactant Structure on

Control Performance. Colloids and S 2. 1. Carter, D. K., Hill, E. A. & Monroe, K. R.1

12. Mccoy, M. (2005) “S3. http://media.wiley.com1 (2005).

14. www.epu.jpm.my (2005).

THE OPTIMIZATIO HITIN HYDRO S PARAMETERS BY HYDROCHLORIC ACID BY RESPONSE SURFACE METHODOLOGY

ng, Chee

N OF THE C LYSI

Kah Leo & Osman, HSchool of Chemical Food Technology, Faculty of Science & Technology,

National Uni of Malaysia, 43600 Bangi, Selangor, Malaysia. e email: osman @ ukm.my

Abstract

Acid hydrolysis of chitin is a conventional method to produce N-acetyl-D-glucosamine. The

performance of 6 types of acid hydrolysis (6N HCl, 6N CH3COOH, 6N H2SO4, 6N HNO3, 85% H3PO4, and 6N CCl3COOH have been studied through high performance liquid chromatography analysis. Then, the response surface methodology was applied to optimize the acid hydrolysis parameters (substrate concentration, acid concentration and temperature) for the N-acetyl-D-glucosamine production. Throughout the screening, the 6N HCl hydrolysis produces the highest yield of N-acetyl-D-glucosamine (0.496%), followed by 6N HNO3, 6N CH3COOH, 6N CCl3COOH, 85% H3PO4 and 6N H2SO4, hydrolysis that produce 0.285%, 0.240%, 0.117%, 0.032% and 0.009% of N-acetyl-D-glucosamine respectively. Therefore, HCl was chosen to optimize the production. The concentration of substrate (CC-RBB), HCl concentration and temperature were significant factors after analyzed by 23-1 fractional factorial design. The steepest ascent method was used to locate the optimal domain and a central composite design was used to estimate the quadratic response surface from which the factor levels for maximum absorbance were determined. The optimal conditions of concentration of substrate (CC-RBB), HCl concentration and temperature at which maximum amount of N-acetyl-D-glucosamine formed were found to be 140mg/ml of CC-RBB, 10.18M of HCl concentration, 90oC, and 2.5 hours respectively. The higher yield of N-acetylglucosmine was produced using colloidal chitin (11.96%) compare to chitin (10.40%) as substrate.

e; Optimization; Response surface methodology.

1.0 Introduction

mer on

er. Recently,

hich have a bitter taste, GlcNAc has a sweet taste that facilitates its use in daily consumption. However, GlcNAc has not been widely commercialized mainly due to the lack of an economical process for its production that is acceptable for food and medicine.

Currently, N-acetyl-D-glucosamine is produced by the acetylation of glucosamine, a product

ble of reaching the true optimum due especially to mes that the various hydrolysis parameters do not

interact and the process response is a direct function of the single varied parameter. In contrast, the observed hydrolysis results arise from the interactive influences of the various variables. Unlike

. Sciences &versityCorrespondenc

Keywords: Acid hydrolysis; Chitin; N-acetyl-D-glucosamin

Chitin, a β-(1→4)-linked 2-acetamido-D-glucopyranan, is the second most abundant biopolyearth (1). Enzymatic or acid hydrolysis of chitin produced oligosaccharides consisting of β-(1→4)linked N-acetyl-D-glucosamine (2-acetamido-2-deoxy-D-glucose; GlcNAc) and monomGlcNAc have been promoted as a treatment or as nutraceutical agents for patients with osteoarthritis and inflammatory bowel disease [2, 3]. Since GlcNAc is also a component of proteoglycan and a part of GlcN is transformed to GlcNAc by metabolism procedure, the therapeutic activity on osteoarthritis for GlcNAc would be similar to that of GlcN. In contrast to GlcN hydrochloride or sulfate, both of w

of the acid hydrolysis of chitin. That process is limited by poor yields and the availability of raw materials such as crab shells [4]. Therefore, the optimization of the acid hydrolysis is important. Many factors such as substrate concentration, acid concentration, temperature and time are important variables affecting the production of N-acetyl-D-glucosamine. It is difficult to find the most important factors and to optimize them via classic or empiric methods because they have several limitations toward complete optimization. Actually, the traditional one-factor at a time approaches to optimization is time-consuming and incapainteractions among the factors. Moreover, it assu

conventional optimization, statistical optimization methods can take into account the interactions of variables in generating the process response [5].

Factorial design of optimization experiments is especially suitable to account for the interactions. A combination of factors generating a certain optimum response can be identified through factorial design and the use of response surface methodology [6]. Response surface methodology, an experimental strategy for seeking the optimum conditions for a multivariable system, described first by Box and Wilson [7], is a much more efficient technique for optimization [8]. This method had been successfully applied to the optimization of medium composition [9, 13], conditions of enzymatic hydrolysis [10], parameters of food preservation [11] and fermentation processes [12].

In this study, we applied the experimental study for response surface design to examine the acid hydrolysis process of chitin. This will allow one to choose the best condition for produce the N-acetyl-D-glucosamine. As a preliminary study, fractional factorial design (FFD) was used for screening factors that influence GlcNAc production significantly and insignificant ones were eliminated in order to obtain a smaller, more manageable set of factors. By using this method, interactions between variables also can be identified and quantified. After that, the critical subset of factors is focused and finally central composite design is used to examine and optimize this process. Design Expert ® Software Version 6.0 was used as the statistical experimental methods in this study. 2.0 Experimental 2.1 Material Shrimp chitin flake was purchased from Ohka Enterprise Inc. (Malaysia). Acids and alkalis (HCl, CH3COOH, HNO3, H3PO4, CCl3COOH, H2SO4, NaOH) of analytical grade were obtained from E. Merck (Darmstadt, Germany). Sigma Chemicals (Malaysia) supplied the standards of GlcNAc, Remazol Brilliant Blue R (RBB) and chemicals for the dyeing reaction.

.2 Colloidal chitin preparation

Te laboratory hammer mill (IKA-WERKE) and to particles of 0.2 obtained powder was added in 300ml of 85% phosphoric acid and kept in a refrigerator (5°C) for 24 h. Thereafter, 2 l of distilled water were added and the gelatinous white material formed was separated by filtration through filter paper. The retained cake was washed with distilled water unt s pH ]. 2.3 material [ 5] Two hundred grams of colloidal chitin were homogeneous with 400 ml of an aqueous solution of RBB at 5.0%. The resulting suspension was heated in a boiling water bath for 60 min with gen he colloidal aterial was removed by filtration and, to fix the RBB-colour, the

was suspended in 25 ml of an aqueous solution of 1.5% sodium dichromate m tartrate, without any pH adjustment, followed by heating with gentle

tirring into a boiling water bath for 10 min. The dyed material was then separated by filtration and

under vacuum. The solid particles obtained after drying were redissolved in 50 mL deionized water.

2

n grams of chitin were ground in a5mm. The

il the filtrate achieve 6.5 [14

Dyeing of chitinous 1

ly mixed

tle stirring. T dyed mobtained material as such and 1.5% sodium potassiuswashed with hot water until the filtrate was colorless. The gelatinous blue material obtained was sterilized by autoclaving, and freeze dried. 2.4 Preparation of Acid Hydrolyzed Samples For acid screening, 5 g of chitin powder was added into 100 mL of 6N (HCl, CH3COOH, HNO3, CCl3COOH, H2SO4) and 85% of H3PO4. The sample solution was in a water bath maintained at a constant temperature of 90ºC for 2 hours. Then, the residue was filtered by the Whatman No.1 filter paper. The 50-mL sample solution was quickly cooled in an ice bath, freeze-dried at -40ºC

The above drying and dissolution processes were repeated twice to remove as much residual acid as possible. The 50 mL sample solution was then neutralized with 1N NaOH, followed by filtration

rough Whatman no. 1 filter paper to remove impurities. The filtrate was concentrated by ntration was around 1mL. Methanol (HPLC

grade, 19m s then add precipitate har ’s metsolution was filtered through a Whatman membrane filter (0.45 µm pore size, 13 mm diameter) before HPLC jection. hydrolyz ample of the optimum condition is the samethe optimum eters. 2.5 Quantific on of GlcNA The identification and amount of GlcNAc was determined using HPLC analysis w Waters lchromatograph (Millipore ilford, MA . The HP em was f ith a W

525 binary HPLC pumps, a Waters 717plus autosampler and a Waters 2414 RI detector. A prevail carbohydrate column (5 µm, 4.6mm X 250 mm) from ALLTECH was used to elute GlcNAc

2.6 Experimental design A series of statistically designed studies were performed to investigate the effect of 3 factors on prod

i. The factors and coded values of FFD are shown in able 1 he linear model obtained is expressed as follows:

thevaporation under reduced pressure until the final conce

L) wa ed to oligosacc ides with DP ≥8 [16]. The hanolic

in The preparation ed s with param

ati c

ith a iquid Corp., M , USA) LC syst itted w aters

1

isocratically at 0.8 mL/min with 70% acetonitrile ratio to 30% deionized water (0.1% NH4OH).The injection volume was 20 µL. For the quantification of hydrolyzed samples, standard solutions of GlcNAc (containing 500 ppm of each GlcNAc) were used for calibrations before daily analysis. The ratios between the peak areas of samples and standards were used to calculate the weight of GlcNAc in the original hydrolysate solution.

ucing GlcNAc. The optimization process first entails identifying the most important factors in this process and then focusing on the critical subset of factors. The steepest ascent was used to determine the direction toward predicting higher responses. Finally a central composite design was performed to optimize the critical factors and optimize the process. A 23-1 full factorial design (FFD) was used to pick factors that influence GlcNAc production significantly and insignificant ones were eliminated in order to obtain a smaller, more manageable set of factors. In FFD, low and high factor settings were coded as –1 and +1 , the midpoint was coded as 0. Factor settings were shown in the form of both coded values and natural values. Xi = (xi-xi0) / δi, where Xi is the coded value, xi is the corresponding natural value, xi0 is the natural value in the center of natural domain and δi is the increment of xi corresponding to 1 unit of XT . T

1i i

k

iy xοβ β+

=

= ∑ Eq (1)

the mean of the center points exceeds the mean of factorial points, the optimum would be near or ithin the experimental design space. If the mean of the center point had been less than the mean of ctorial points, the optimum would be outside the experimental design space and the method of

teepest ascent should be applied. The direction of steepest ascent is parallel to the normal of contour ne of response curve of equation (1) and passes through the center point of FFD [17].

In this study, full factorial was chosen to determine the significant effect in producing lcNAc. By using 23-1 design, 16 runs are required for duplicate. 6 center points were added to

stimate the experimental error and check the adequacy of the first-order model. Table 1 shows the ctors and coded values of FFD.

odel,

s a star configuration to estimate quadratic effects and central points to estimate

Ifwfasli

Gefa

Once critical factors were identified via screening and significant gross curvature has beendetected in the design space, the central composite design was proceeded to obtain a quadratic mconsisting of trials pluthe variability and reassess gross curvature, with GlcNAc production as response. For two factors, themodel obtained was expressed as follows:

2 22 12 1 2 22 22y x x x xοβ β β+ + + += Eq (2)

whe was the response, the interce , β1 bone a ere linear c nts, β11 and β22 were quadratic coefficients, and x1 and x2 were coded indepen riables. Low and high factor settings were coded as –1 and +1, the midpoint ded as 0. T r settings o hat ran along axes drawn from the middle of the cube th he centers of each face of the tube were code s +1.414 . The exp tal design and results is showed in Table 3. Design Expert Version 6 was used to analyze the re Table 1: Factors and coded values o

of factors

1 1 2 11 11+xβ β xβ

re y measured βo was pt term nd β2 w oefficiedent va

was co he facto f trails trough t

d a or –1.414 erimensults.

f FFD

Level Factor0 +1

s -1

Tem ature (x1 80.0 100.0 per , ºC) 60.0 Acid conc. (x2, M 6.0 8.0 CC-RBB weight 5.5 10.0

) 4.0 (x3, mg) 1.0

2.6 Assay with R

R-NHCOCH3 + H+X- → R-N+HCOCH3X- Eq (3)

Actual

mmol x kg-1

BB [15]

One milliliter of HCl with different concentration (4, 6 & 8M) respectively was added into every treatment respectively as shown in Table 3. After 2.5 hours, the tubes are put into the ice water for 10 minutes. Then, 1ml NaOH with the suitable Molarity (4, 6 & 8M) was added to neutralize the hydrolysate. The dilution of sample was with adding 10mL of distilled water. The tubes were centrifuged at 7000 rpm and the absorbance of the supernatants was read with Versamax microplate reader at 595 nm.

.0 Results and discussions 3 3.1 Screening of best acid

Throughout the screening for six types of acid in the preliminary study, only the 6N HCl hydrolysis produces the highest yield of N-acetyl-D-glucosamine (0.496%), followed by 6N HNO3, 6N CH3COOH, 6N CCl3COOH, 85% H3PO4 and 6N H2SO4, hydrolysis that produce 0.285%, 0.240%, 0.117%, 0.032% and 0.009% of N-acetyl-D-glucosamine respectively. The first reason is relevant to the chitin adsorption of acid ability. According to Giles et al. 1958 [18], the acid binding capacity value is 4.8 eq X kg-1 at pH 2.0. At lower pH value a sudden futher rise in absorption occurs and proceeds without apparent limit. Once the acetamido and amino groups are saturated, no other acid combining group will be available unless the ether groups form oxonium salts. Even if this were so, the total quantity of acid could not be accounted for. Therefore, the general reaction would be:

ly, the acetamido and amino groups of chitin are the only operative groups toward hydroxylic solutes. The hydroxyl and ether groups on the glucosidic rings are probably protected by solvated water and thus rendered inactive. Table 2 shows the adsorption of acids by chitin at 50°C and pH 3.0 for various types of acids where the value for HCl and H2SO4 are the highest. Table 2: Adsorption of acids by chitin.

Acid

Hydrochloric 3800 Formic 385 Acetic 255 Chloroacetic 320 Sulfuric 3870 Nitric 235 Benzesulfonic 200

On the other hand, the acid strength plays the vital role because the first step in the acid

hydrolysis of chitin is the amine group is protonated and the C(2)-NH3 group shields the glycosidic oxygen from protonation [19]. The BrØnsted-Lowry theory defines acid strength in terms of proton-donating tendency. The greater the tendency of a substrate to donate a proton, the greater is its acid strength; and the higher value of ionization constant (Ka). During the acid hydrolysis, the chain scission appears to occur in random. Therefore, the HCl, H2SO4, and HNO3 should have the higher yield of h

dimer and is phenom na does not fit the pattern expected for random splitting of the chain, but Rupley explained

that the rate-limiting step is a disaggregation step,

sis occurs at the time of dissolution, the subsequent being slower. Secondly, the chain scission appears to occur at random; after 4 h

C in 96 wt-% H2SO4 the number average DP of the dialyzable fraction, which ounted to 94 % at -20°C

ot the monomer,

3.2 Optimization of N-acetylglucosamine production

Fractional factorial design

pe 3-1

Y = 0.21 + 0.018 x1 + 0.087 x2 +0.170 x3+ 0.028x1 x2+0.019 x1 x3+0.059 x2 x3+0.029 x1 x2 x3 Eq (4)

land th

safactor

_____

ydrolysis [20]. efer to the results, HCl hydrolysis produce the highest yield followed by HNO hydrolysis, butR 3

the H2SO4 hydrolysis produce the lowest quantity. Why? Rupley (1964) reported that the monomer, trimer were found to be the predominant species of the chitin hydrolysis by HCl [19]. Th

ethat the chitin chain are aggregated in solution and followed by rapid hydrolysis. Hydrolysis of chitin by H2SO4 is different with HCl. According to Nagasawa et al. (1971), the most obvious being that chitin hydrolysis is accompanied by O-sulphation of chitin. Therefore, the greatest hydrolyhydrolysis in solution hydrolysis at 5°am of the product, was 16, while all the products for hydrolysis times of 1-6 h were non-dialysable. Thus, unlike hydrolysis by HCl, the predominant species are ndimer and trimer [21].

3.2.1

According to the results above and primary studies, HCl was selected as the hydrolyzing agent for chitin hydrolysis. The concentration of substrate (CC-RBB), HCl concentration and

rature were the main factem tors to optimize the medium composition using 2 full factorial design (FFD). Real values of factors, design and results of experiment were shown in Table 3. The factorial analysis of variance indicated that all factors and interactions are giving the significant influences to the acid hydrolysis, especially CC-RBB weight give the most significant impact to the acid hydrolysis due to the highest coefficient estimate value (0.17) (Table 4). A linear regression equation could be obtained from the regression results of fractional factorial experiment:

The regression coefficients and determination coefficient (R2) for the linear regression model of N-acety glucosamine production are presented in Table 4. The model was highly significant (p < 0.0001)

e lack of fit (p= 0.2060) is insignificant indicating that the first-order model is very adequate in approximating the response surface of the experimental design. This statement is further supported by the tisfactory value of R2 = 0.9907. The mean of center point (0.165) is lower than the mean of

ial points (0.19) indicated that optimal point is outside the experimental design space and the method of steepest ascent should be applied. Table 3: Experimental design and results of FFD

___________________________________________________________________ Factor 1 Factor 2 Factor 3 Response 1

Run Block A:Temperature B:Acid conc. C:CC-RBB wt. Adsorbance deg C M mg A

2 0.456

7 k 1 100.00 4.00 1.00 0.006

9 10 100.00 8.00 1.00 0.065

17 50

19 1.00 0.006 20 10.00 0.249 21 Block 2 100.00 4.00 1.00 0.005 22 Block 2 80.00 6.00 5.50 0.151 23 Block 2 80.00 6.00 5.50 0.181 24 Block 2 80.00 6.00 5.50 0.150 25 Block 2 100.00 4.00 10.00 0.197 26 Block 2 60.00 8.00 1.00 0.059 27 Block 2 60.00 8.00 10.00 0.404 28 Block 2 80.00 6.00 5.50 0.180

______________________________________________________________________________________ 1 Block 1 100.00 4.00 10.00 0.226

Block 1 80.00 6.00 5.50 0.151 0 3 Block 1 60.00 8.00 10.0

4 Block 1 100.00 8.00 10.00 0.657 5 Block 1 80.00 6.00 5.50 0.181 6 Block 1 80.00 6.00 5.50 0.150

Bloc 8 Block 1 80.00 6.00 5.50 0.180

Block 1 80.00 6.00 5.50 0.151 Block 1

11 Block 1 60.00 8.00 1.00 0.069 12 Block 1 80.00 6.00 5.50 0.181 13 Block 1 60.00 4.00 1.00 0.005 14 Block 1 60.00 4.00 10.00 0.257

Block 2 100.00 8.00 10.00 0.578 15 16 Block 2 100.00 8.00 1.00 0.054

Block 2 80.00 6.00 5.50 0.1 18 Block 2 80.00 6.00 5.50 0.180

Block 2 60.00 4.00 Block 2 60.00 4.00

Table 4: Coefficient value and p-value for the factors

Factor Coefficient Estimate p-value Intercept 0.21 Block 1 6.821E-003 Block 2 -6.821E-003 A-Temperature (X1) 0.018 0.0015 B-Acid conc. (X2) 0.087 < 0.0001 C-CC-RBB wt. (X3) 0.17 < 0.0001 AB 0.028 < 0.0001 AC 0.019 0.0009 BC 0.059 < 0.0001 ABC 0.029 < 0.0001 Center Point -0.040

3.2.2 Steepest ascent path The direction of steepest ascent path can be determined by Eq. (4) and regression results. All the factors were significant and their coefficients are positive. This means that increasing the temperature, acid concentration and CC-RBB weight will have positive effects on the N-acetylglucosamine production. CC-RBB was chosen as standard because its coefficient is the biggest. Design of experiment of the steepest ascent and corresponding results are shown in Table 5. GlcNAc production of OBS 5 was the highest (0.861A), then adsorbent decreased following the concentration changing. The results mean that factors value of OBS 5 was near optimal, thus OBS 5 was chosen as the center point to optimize the medium composition. This result is agreed with the statement of a hydrolysis mechanism in which the physical arrangement of the chitin chains is important in

determining the kinetic behaviour is in agreement with the observed high reaction order with respect tration [19]. to acid concen

Table 5: Results of the steepes

OBS. Step A(Temp.) B(Acid conc.) C(CC-RBB) Response A

t ascent path experiments

°C N % 1 Source (Median) 80 6 5.5 0.235 ∆ 0.106 0.512 1

S+ 2∆ 80.212 7.024 7.5 -

2 0.266 3 S+ 4∆ 9.5 0.364 4 S+ 6∆ 80.636 9.072 11.5 0.645

80.424 8.048

5 S+ 8∆ 80.848 10.096 13.5 0.861 6 S+ 9∆ 80.954 10.608 14.5 0.853 7 S+ 10∆ 81.060 11.120 15.5 0.843

3.2.3 Central composite design A highly significant regression model (p< 0.0001) for N-acetyl-glucosamine production with a satisfied R2 = 0.9589 was achieved. According to the insignificant Lack of Fit value (p= 0.1626), this model is suitable for the screening experimental design. Experimental design and results are shown in Table 6. A full second-order polynomial model was

maximum response predicted from the model was 0.1414A. tions

.e., 0.140, 0.142, 0.141, 0.142, 0.140 A) was coincident with the predicted value and the model was meters optimized with RSM are: 90oC, 10.18M of HCl

oncentration, 14mg of CC-RBB and 2.5 hours. The optimum time course of chitin hydrolysis is 2.5 h

obtained from regression analysis of data of experiment of central composite design: Y = 0.13 +1.474E-003 X1 ++3.531E-003 X2 +4.240E-003 X3 +1.282E-003X1

2-4.021E-003 X22

+4.287E-003 X32 -2.125E-003X1 X2 Eq (5)

The resulting response surface showed the effect of CC-RBB weight, acid concentration and

temperature on the N-acetylglucosamine production (Fig. 1). The maximum yield was obtained in the optimized condition when the temperature, concentration of acid and CC-RBB weight were 90oC,

0.18M and 14mg respectively. The 1Repeated experiments were performed to verify the predicted optimum. The result of five replica(iproven to be adequate. The final paracbecause the chitin had been fully hydrolyzed.

DE S IGN-E X P E RT P lo t

Des i rab i l i tyX = A : T em pera tu reY = B : A c id c onc .

A c tua l Fac torC: CC-RB B wt. = 140 .00

0.616

0 .698

0 .779

0 .453

0 .534

Des

irabil

ity

70 .00

75.00

80 .00

85 .00

90 .00

9 .00

9 .50

10.00

10 .50

11.00

A: Temperature B: Acid conc.

Fig. 1. Response surface plot for the effect of temperature (X1) and acid concentration (X2) on GlcNAc production. Table 6: Design and results of central composition design

Run Block A: Temp. B: Acid conc. C: CC- RBB wt. Response

1 Block 1 90.00 9.00 14.00 0.136 2 Block 1 96.82 10.00 13.00 0.138 3 Block 1 80.00 10.00 11.32 0.134 4 Block 1 90.00 9.00 12.00 0.127 5 Block 1 80.00 11.68 13.00 0.126 6 Block 1 80.00 10.00 13.00 0.132

0.128 12.00 0.122

0 0.130 11 Block 1 80.00 8.32 13.00 0.111

7 Block 1 80.00 10.00 14.68 0.150 8 Block 1 80.00 10.00 13.00 9 Block 1 70.00 9.00

10 Block 1 70.00 9.00 14.0

12 Block 1 70.00 11.00 14.00 0.138 13 Block 1 90.00 11.00 14.00 0.138 14 Block 1 80.00 10.00 13.00 0.130 15 Block 1 80.00 10.00 13.00 0.131 16 Block 1 63.18 10.00 13.00 0.129 17 Block 1 70.00 11.00 12.00 0.134 18 Block 1 80.00 10.00 13.00 0.130 19 Block 1 80.00 10.00 13.00 0.129 20 Block 1 90.00 11.00 12.00 0.128

According to Muzzarelli (1977) [18] and Smucker & Pfister (1978)[22], 4-6 N HCI hydrolysis at

in particles could only be hydrolyzed under higher HCl concentrations [23]. The hydrolysis at higher temperatures favored the formation of lower molecular weight oligosaccharides. The amount of (GlcNAc)6 or (GlcNAc)5 obtained at 90ºC was much lower than that obtained at 70ºC (Chang et al.,

000) [24]. Therefore, the optimum HCl concentration is 10.18M.

.3 Quantification of GlcNAc by HPLC analysis

d after treatment f HCl on chitin and colloidal chitin. The higher yield of N-acetylglucosmine was produced using

colloidal chitin (11. d parameters have th f N-acetylglucosamine almost 21 times compare to the screening

s o is by using HCl. Major variable in chitin substrates is the degree of crystallinity or fiber-openness to the

hyd ysing agent attachment. In th t work, the swelling of the substrate through phosphoric acid treatment m substanti sed its intia to HCl. The higher am t of N-ace samine production for colloidal chitin in the present work probably results fr opening u he polymer and the exposure of centre phase of the colloid [25].

. Conclusions

Chloric acid is a suitable sin l-D-glucosamine, especially by using colloidal chitin as the subst proved to be quite adequate for the design and optimization of a hydrolysis process. Using the method of experimental factorial design and response surface analy as possible to determine optimal condition to obtain high N-acetyl-D-glucosamine production. In addition to establishing optimal condition for operation, the present methodology also makes it possible to predict yield and productivity when the system is disturbed in some way. This is useful not only for the additional knowledge supplied about the

rocess, but also for the potentials for process control.

100°C for 12-20 h is necessary to achieve complete chitin hydrolysis. Weaker acid hydrolysis such as 0.5-2.0 N HCI or 0.5 M H2SO4 is ineffectual in chitin hydrolysis, but is more than sufficient for most non-amino sugar hydrolyses. Chen et al. also reported that the yield of NACOs became higher than 60% by hydrolyzing chitin with 10 N or 12 N HCl at 50ºC because some portion of chit

2 3

Figure 2 shows the HPLC chromatograms of the hydrolyzed samples obtaineo

96%) compare to chitin (10.40%) as substrate. The optimizeincreased parameter

e production of chitin hydrolys

rol e currenay have ally increa l accessibility relatively

oun tylglucoom an p of t

4

hydrolyr This

g agent to produce N-acetymethodolog as a whole ate. y

sis it w

both

p

A B C

Figure 2: HPLC elution p files of (A) a sugar standard from mon er, (B) a typical acid hydrolyzed chitin sample; and (C) a acid hydrolysed colloidal chitin sample.

This work was supported by grant 09-02-02-0006/BTK/ER/31 from National Biotechnology Directorate (BIOTEK), MOSTI, Malaysia. 6.0 References 1. Knorr, D. (1984) Use of chitinous polymers in food. Food Technol. 38: 85-97.

. Ther. 18: 1184–1190.

mixture of

omer to tetramro

5.0 Acknowledgements

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12. Rosi, I., Costamagna, L. & Bertuccioli, M. (1987) Wine fer

13. Souza, M.C.de O.

16. Muraki, E., Yaku, F. & Kojima, H. (1993) Preparation and crystallization of D-glucosamine oligosaccharides with dp 6-8. Cabohydr. Res. 239: 227-237.

17. Tang, X.J., He, G.Q., Chen, Q.H., Zhang, X.Y. & Mokhtar, A. M. A. (2004) Medium optimization for the production of thermal stable β-glucanase by Bacillus subtilis ZJF-1A5 using response surface methodology. Bioresource Technology 93.I2: 175-181.

accharides by sulfuric acid Carbohydr. Res. 18: 95-102

22. Smucker, R. A. & Pfister, R. M. (1978) Characteristics of Streptomyces coelicolor A3(2) aerial spore rodlet mosaic. Can. J, Microbiol. 24: 397-408

23 Chen, K. S., Huang, P. F., Chen, T. S. and Chen, H. C. (1996) Investigation of hydrolytic conditions on the preparation of N-acetylchitooligosaccharides. Food Sci. 23: 874-883.

24 Chang, K.L.B., Lee, J. & Wen, R.F. (2000) HPLC analysis of N-acetyl-chito-oligosaccharides during the acid hydrolysis of chitin. Journal of Food and Drug Analysis. 8(2) : 75-83

25. Smucrer, R.A., & Wright, D.A. (1986) Characteristics of Crassostrea virginica crystalline chitin digestion. Comp. biochem. Physiol. 83A/ 3: 489-493.

18. Muzzarelli, R. A. (1977) Chitin. Pergamon Press, New York. pg 108 19. Roberts, G.A.F. (1992) Chitin chemistry. The Macmillan Press Ltd. Hong Kong. pg 249-253. 20. Hand, C.W. & Blewitt, H.L. (1986) Acid-base chemistry. Macmillan Publishing Company. New

York. pg 11-47. 21. Nagasawa, K., Tahira, Y., Inoue, Y. & Tanoura, N. (1971) Reaction between carbohydrates and

sulfuric acid : Part I. Depolymerization and sulfation of polys

LONG-TERM STUDIES ON THE SALINITY (TDS) AND LEACHING CHARACTERISTICS OF COAL FLY ASH FROM TNB POWER GENERATION PLANT

Khoo 1,* 2 Kok Siong , Sukiman Sarmani

1,*Nuclear Science Program, School of Applied Physics, Faculty of Science and Technology,

National University of Malaysia, 43600 Bangi, Selangor, Malaysia, 2Program of Chemistry and Food Technology, School of Applied Chemistry, Faculty of Science and

Technology, National University of Malaysia, 43600 Bangi, Selangor, Malaysia. e-mail: [email protected]

Abstract. Use of coal in power generation plant has led to increasing environmental concern especially in disposal of ash residues. The problem related to coal fly ash disposal is the constituents of the residue. In this regard, three laboratory leaching test methods consisted of the pore water test (PW), the acid neutralization capacity test (ANC) and the tank leaching test (TL) have been carried out. Subsequently, study on leaching behaviour of salinity (TDS) from coal fly ashes was reported. In Pore water test (PW), it was found that the total dissolved solids (TDS) decreased when the liquid/ lid ratios (L/S) increased. In Acid neutralization capacity test (ANC), TDS only increased rapidly in higher acid and base concentrations (molarities). In Tank leaching test (TL), cumulative release (g/m2) was ranged from 151 to 448 g/m2 in 64 days respectively. The studies indicated that the results are pH supported. Abstrak. Penggunaan arang batu di janakuasa elektrik telah memberikan kerisauan terhadap alam sekitar terutamanya pembuangan dan sisa abu arang batu. Masalah yang dikaitkan dengan abu terbang arang batu ialah kandungan unsure-unsur dalam sisa tersebut. Sehubungan itu, tiga kaedah ujian larut resap iaitu ujian PW, ujian ANC dan ujian TL telah dilakukan. Seterusnya, kajian terhadap kelakuan larut resap bagi paras kandungan garam (TDS) pada abu terbang arang batu juga dilaporkan. Dalam ujian PW, didapati bahawa paras kandungan garam (TDS) menurun apabila nisbah cecair/pepejal (L/S) meningkat. Dalam ujian ANC, TDS hanya meningkat dengan cepat pada kepekatan asid dan bes yang tinggi. Dalam ujian TL pula, pembebasan kumulatif (g/m2) adalah dalam julat 151 – 448 g/m2 dalam 64 hari masing-masing. Kajian ini telah menunjukkan bahawa keputusan adalah bergantung kepada pH.

Keywords: Coal fly ash, salinity (TDS), pore water test, acid neutralization capacity test, tank leaching test Introduction Tenaga Nasional Berhad (TNB) is the largest power company in Southeast Asia, TNB generates two-thirds of the electricity on the Malaysian Peninsula. It operates the national power transmission and distribution grid, which serves more than 6 million residential, industrial, and commercial customers. Kapar coal fired power generation plant is the first coal based power plant commissioned since 1988 with 2x300 MW units and additional 2x500 MW units in 2001. The rapid development in Malaysian economy has resulted increase of coal consumption. One of the by-products produced from power generation plant is coal fly ash (the non-combustible minerals found in coal). The coal fly ash is subsequently removed, transported and deposited which may create problem of its disposal. Charac l step in the nvironmental assessment for reuse or disposal reasons. Recent awareness and empowerment of the

public on the environmental concern has resulted in the need for the assessment of its behaviour. Leaching is the process by which constituents in a solid material, which in this case as coal fly ashes, is released into environment via contact with water. The interest of knowing the leaching process is to define the potential environmental impacts via water-borne mechanisms involving the contamination of soil, groundwater and surface water; human health from advantageous use and disposal of wastes; designs and acceptance criteria for waste management facilities and degradation of structural performance of certain elements in the environment. Coal fly ash is generated from the combustion of coal in power generation plant boilers and ollected from off-gas combustion in electrostatic precipitators. Typical coal fly ash particles ranged

in size up to 1-150 µm and their composition depends on the nature of the coal being burned [1]. The coal fly ash is utilized in applications of the cement and concrete industry, such as structural filling material and recovery of metals [2]. However, the rate of production is greater than the consumption.

so

terization of the leaching behaviour of coal fly ashes is a cruciae

c

The unused coal fly ash is disposed into holding ponds, lagoons, landfills and heaps. The bulk of the coal fly ash normally consists of silica (SiO2), alumina (Al2O3), iron oxide (Fe2O3), calcium oxide (CaO), magnesium oxide (MgO), potassium oxide (K2O), sodium oxide (Na2O), sulfur trioxide (SO3), titanium dioxide (TiO2) and significant quantities of various trace elements such as Ba, Co, Cr, Ga, Nb, Ni, Rb, Sr, V and Zr [3]. Other nutrients usually present in coal fly ash are P and B and radioisotopes that are undesirable for animals and human [4]. The release of metals from coal fly ash is influenced by different physical, chemical and biological factors. In particular, the leaching studies can be divided into three categories: a) characterization tests for the characterization of materials; b) compliance tests for verifying agreement with the characterized material; c) in situ tests to verify the identity of a waste before its disposal or recovery. In this framework, study has been carried out on three laboratory leaching characterization test methods for the assessment of the leaching behaviour of salinity (dissolved solids) from coal fly ashes. Salinity is simply a measure of the amount of salt dissolved in water. Salts such as sodium chloride (NaCl), calcium carbonate (CaCO3) and others are picked up by water as they run over and through the soils of catchments. Low concentrations of these salts are important to the growth of plants and animals but high concentrations can be problem for aquatic life and human uses such as crop irrigation and ground water. Salinity can be measured directly using total dissolved solids (TDS) method. It is measured as mg/L and although not identical to the true salinity but it is close enough for most purposes. These three experimental tests comprised two equilibriums and one dynamic test [5]: a). The Pore Water Test (PW), which assessed the beginning equilibrium composition of the pore solution and the soluble species M

) d Influence of pH on leaching with initial acid/base addition”. The purpose of the test was to study the

influence of pH on the leach ability of inorganic species from ash material by addition of predetermined amounts of acid or base to desired end pH values in steady state condition. c). The Tank Leaching Test (TL), which allowed to determine the leaching behaviour of granular ashes under dynamic conditions. It was used to determine the dominant release mechanisms of inorganic species from regularly shaped specimens of monolithic wastes [6]. Methodology Five samples namely B, C, L, M and ASP based on different kinds of coal fly ashes are considered. The details of the coal fly ashes are shown in Table 1, Table 2, Table 3 and Table 4.

Table 1. Sources and physical characteristics of coal fly ash.

Sample Type of fly ash Type of coal Specific gravity (kg/m3) Melting point (0C)

aximum Mobile Fraction (MMF) for leaching. . The Acid Neutralization Capacity Test (ANC), which is inspired from the European pre-standarb

“

B Coarse Bitumen C Fine Lignite L Coarse Bitumen M Coarse Bitumen

ASP Fine Bitumen

2050 - 2300 > 1400

Table 2. Liquid/Solid ratio of coal d in PW. Applied to other as well. fly ash useLabel Liquid/Solid ratio (L/S)

B1 1 B5 5

B10 10 B50 50

B100 100 B200 200

Table 3. Liquid/Solid ratio and pH of coal fly ash used in ANC. Applied to other as well. Label Liquid/Solid ratio (L/S) pH B_1 1 B_2 3 B_3 5 B_4 7 B_5 10 B_6

10 ml/g dried fly ash

12 B_7 14

Table 4. Liquid/Surface ratio, area and pH of coal fly ash used in TL.

Sample Liquid/Surface ratio (L/S)

Area (cm2) pH

B C L M

ASP

80 x Area 5.31 4

a). re Water Test (PW) Po

n ash and in re during ay

ondThe cplotti

e s

porospH vac). Ta

te t wvesse face ratio of

cmto preafter alyzed after filtration (filter porosity: 0.45 µm). The plotting of pH against duration, and total dissolved solids (TDS) against days are showed in Figure 3 and 4. The total dissolved solids (TDS) were measured using calibrated HACH C0150 Conductivity Meter with HACH model Conductivity Probe 50161 k=1.0 and pH values were recorded using calibrated microprocessor pH meter (Hanna Instrument pH 211). Results and Discussion Figure 1 shows the total dissolved solids (TDS) of different coal fly ashes in equilibrium state. The decrease of TDS on the L/S ratios supports the hypothesis that the leaching available quantities deduced from the test for the soluble salts. It also can be noticed that, in general, TDS of sample C, L and M are quite similar with the magnitude of C>L>M. On the other hand, TDS of sample B is approximately three times higher than sample C whereas ASP coal fly ash is the highest among the samples. The result showed that the pH levels of the solutions were still in the range of 6.5 – 8.0. As expected, without any binder which normally gives alkaline solution, the pH levels have not changed

This test allows the evaluation of the species solubilization at steady state conditions betweedem eralised water in closed vessels for different liquid/solid ratios (L/S) at room temperatu7 d s of continuous shaking [5]. The samples were put into contact with demineralised water (C uctivity: 1.15±0.07 µS/cm; TDS: 0 mg/L; pH~7) for L/S ratios: 1, 5, 10, 50, 100 and 200 ml/g.

losed vessels were shook for 7 days and then were filtered using 0.45 µm membrane filter. The ng of total dissolved solids (mg/L) to L/S ratio is showed in Figure 1.

b). Acid Neutralization Capacity Test (ANC) Th amples were put into contact with demineralised water for L/S ratio of 10ml/g in all the parallel running samples. The closed vessels were shook for 7 days at room temperature. After filtration (filter

ity: 0.45 µm) the solution was analyzed. The plotting of total dissolved solids (mg/L) to different lues of samples is showed in Figure 2. nk Leaching Test (TL)

This test was modified from the compact granular protocol of Tank Leach Test NEN 7345 [7]. The s as carried out on 4 granular cylindrical samples. The fly ash was embedded to polyethylene

l and the leach was demineralised water which acidified to pH of 4. The Liquid/Sur80/ 2 was remained constantly throughout the test. The polyethylene vessels were used and closed

vent the intake of CO2 and water evaporation during the leaching test. The leach was renewed 0.25, 1, 2, 5, 8, 21, 36 and 64 days. Then, 8 eluates were an

too much from neutral. According to Raask [8], the alkaline solution obtained when fly ash is would be attributable to leaching of alkali metals such as Nsuspended in water a, K and Ca from

aluminosilicate fractions of fly ash particles. Aluminosilicate fractions of fly ash particles could increase the OH- concentration in solution. Thus, the dissolution of Na, K and Ca increase the concentration of Ca2+ and OH- ions, and subsequently, this situation will affect pH level in water. ith the magnitude of C>L>M. On the other hand, TDS of B sample is approximately three times higher than C samp amples presented low salin sample was high especially for L/S of 1, 5 and 10. P sample can be assumed that the initial pore water corresponding to the solid phase of the salt properties.

It also can be noticed that, in general, TDS of C, L and M samples are quite similar w

le whereas ASP coal fly ash is the highest among the samples. B, C, L and M se content whereas concentration of total dissolved solids for ASP

The high salts solubility in AS

0

500

1000

1500

2000

2500

3000

3500

4000

B1 B5 B10 B50 B100 B200

TDS

(mg/

L)

0

200

400

600

800

1000

1200

C1 C5 C10 C50 C100 C200

TDS

(mg/

L)

0

200

400

600

800

1000

1200

L1 L5 L10 L50 L100 L200

TDS

(mg/

L)

0

200

400

600

800

1000

1200

M1 M5 M10 M50 M100 M200

TDS

(mg/

L)

4000

6000

8000

10000

12000

TDS

(mg/

L)

6

6.5

7

7.5

8

0ASP1 ASP5 ASP10 ASP50 ASP100 ASP200

2000

0 50 100 150 200

L/S ratio

pH

B C L M ASP Figure 1. Total dissolved solids in PW of the materials.

Figure 2 shows the results of total dissolved solids as a function of ANC of the materials. Regarding to the curves of the samples, we can observe a significant steep decrease curve from each graph and expected to increase rapidly in pH 14. The TDS value is not showed in pH 14 is due to the detection limit of the HACH C0150 Conductivity Meter. Apparently, the actual value would be higher than value in pH 1. From the observation, TDS only increased rapidly in higher acid and base concentrations (molarities). ANC test showed that the change of pH value in solution was

insignificant from pH 3 – pH 10. However, increase of salt concentration in solution was obvious in high molarities. From here, we can assume that with high Ca content of coal fly ash, which is high alkaline property, the high pH values may cause the constituents of coal fly ash probably reach the environment such as groundwater.

012345678

B_1 B_2 B_3 B_4 B_5 B_6 B_7

TDS

(g/L

)

0

1

2

3

4

5

6

7

C_1 C_2 C_3 C_4 C_5 C_6 C_7

TDS

(g/L

)

1000.4

0.45

0.5

0.55

0.6

TDS

(g/

0.65

0.7

0.75

)

L_1

1000

10000

TDS

(mg/

L)

L_2 L_3 L_4 L_5 L_6 L_7

L

100000

M_1 M_2 M_3 M_4 M_5 M_6 M_7

01

ASP_1 P_2 P_3 P_4 P_5 P_6 P_7

23456789

10

TDS

(g/L

)

AS AS AS AS AS AS

otal dissolved solids as a function of ANC of the materials. Figure 2. T From Figure 3, the comparison of pH for Tank leaching test applied to coal fly ashes at room temperature within 64 days has been plotted. The TL test gives the view of physico-chemical of the eluates at the end of each leaching sequence such as released salts and pH values. Initial pH of demineralised water was acidified to pH 4 and what we can see from the graph is the change of the pH value during the duration. Obviously, the pH level of L sample changed instantly from pH 4 to pH 7 within 0.25 day. In the other hand, C sample also showing the change after 1 day following with the ASP sample and B sample increasing slowly. However, M sample was ranged within pH 4.22 – pH 5.48 during the duration.

4

4.5

5

5.5

6

6.5

7

7.5

8

0.25 1 2 5 8 21 36 64t (Days)

pH

L M C B ASP

Figure 3. Comparison of pH for TL applied to coal fly ashes at room temperature within 64 days.

0

50

100

150Cu

200

300

350

400

450

500

5 6 64

t (Days)

tile

ase

(g/m

2)

250

ve re

0.25 1 2 8 21 3

mul

a

B C L M ASP

Figu parison of cumulative release for tem ture in 64 days.

e comparisons of cumu d as flu TL applie fly ashes at room temperature within 64 days. A first look at the experimental results shows ulative release for B, C, L and M mple shows a rapid increa da y-5. From the graphs, we can predict the fluxes for all ll be aturated after 64 days. to P and ANC tests, the eluat ders of magnitude in TL test. The pH-dependent solubility, renewal time and flow of eluate are playing important roles in controlling the release processes.

re 4. Com TL applied to coal fly ashes at room pera

Figure 4 shows th lative release (g/m2) or also calle x for d to coal a low cum samples. However, ASP sase after 0.25 y and continue increasing until da samples wi s Compare W e concentrations are lower or

Conclusion A study has b carried out on y leaching characterization test methods for the assessment of ching behavi from coal fly ashes. Basically, B, C, L and M sa les were showin ly results for the three tests. In the other hand, ASP sample was significantly higher t important role in effecting the

lease of the metals from coal fly ash.

References 1. Roy, D. M., Luke, K., Diamond, S. (1985) “Characterization of Fly Ash and Its Reactions in

Concrete”, Materials Research Society Symposium Proceedings. 43. 3-11. 2. Golden, D. M. (1986) “Epri Coal Ash Utilization Research”, Energy. 11. 1377-1387. 3. Ugurlu, A. (2004) “Leaching Characteristics of Fly Ash”, Environ. Geo. 46. 890-895. 4. Furr, A .K., Parkinson, T. F., Helforn, C. L., Reid, J. T., Haschek, Gutenmann, W. M., Bache,

C. A., St. John Jr., L. E., Lisk, D. J. (1978) “Elemental Content of Tissues and Excreta of Lambs, Goats and Kids Fed White Sweet Clover Growing on Fly Ash”, J. Agric. Food Chem. 26. 847-851.

5. Barna, L., Imyim, A., Barna, R. (2004) “Long-term Prediction of the Leaching Behavior of Pollutants from Solidified Wastes”, Adv. Environ. Res. 8. 697-711.

6. Mehu, J., Moskowicz, P., Barna, R., Sanchez, F. (1997) “Waste Stabilized/Solidified with Hydraulic Binders”, in: Van der Sloot, H. A., Heasman, L., Quevauviller, Ph. (Eds), Studies in Environ e Science, Amsterdam. 171-186.

7. NNI (1994) “NEN 7345: Leaching Characteristics of Building and Solid Waste Materials – Leaching Tests: Determination of the leaching Behavior of Inorganic Components from Shaped Building Materials, Monolithic and Stabilized Waste Materials”, The Netherlands.

8. Raask, E. (1982) “Pulverised Fuel Ash Constituents and Surface Characteristics in Concrete Applications”, in: Cabrera, J. G., Cuseus, A. R. (Eds.), Proceedings of the International Symposium on the Use of PFA in Cncrete, Leeds. 1. 5-16.

een three laboratorthe lea our of salinity (dissolved solids)mp g quite similar

han other. pH has been playing an re

Generally, the environmental impact assessment of coal fly ash leaching scenario requires data like cumulative release, fluxes and concentrations of eluate. Thus, a model for environmental prediction based on laboratory tests will be useful. Acknowledgement The authors wish to thank the financial support from Ministry of Science, Technology and Innovation (MOSTI), Malaysia.

mental Science. Harmonization of Leaching/Extraction Tests. Elsevi r

PENENTUAN KEPEKATAN UNSUR-UNSUR SURIH DALAM TANIH SAWAH DI PERLIS SECARA ANALISIS PENDARFLOUR SINAR-X (XRF)

Pui Vui Ming1,* & Sukiman Sarmani2

1Program Sains Nuklear, Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor. 2Pusat Pengajian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor. e-mail: [email protected]

Abstrak. Kajian ini dilakukan untuk menentukan profil dan pola taburan unsur dalam tanah sawah bagi mengetahui status kesuburan tanah dalam usaha meningkatkan hasil pengeluaran. Kandung

arfluor Sina menentukan

unsur-unsur dalam sampel (dari Z=5 hingga Z=92) pada kepekatan dari julat beberapa mgkg-1 sehingga 100%. Sampel tanih dalam kajian ini telah dikumpul dari kawasan penanaman padi Perlis dalam kawasan MADA. Penyediaan sampel tanih dengan melalui proses pengeringan, pengisahan, penghalusan dan akhirnya penekanan dalam bentuk pellet sebelum dianalisis dan dibilang dengan menggunakan pengesan spektroskopi sinar-X. Sebanyak 16 unsur-unsur surihan iaitu As, Ba, Ce, Co, Cr, Ga, Hf, La, Nb, Pb, Sr, Th, U, V, Y dan Zr berjaya dikesan secara kualitatif dan kuantitatif melalui teknik ini. Taburan kepekatan unsur untuk kebanyakan sampel adalah sekata. Unsur Ba dengan perbezaan kepekatan unsur yang ketara antara 49-1617ppm. Unsur-unsur lain adalah Ce (22-575ppm), Co (1.4-36ppm), Cr (0.3-23ppm), Pb (17-321ppm) dan Th (24-196ppm). Penentuan unsur logam berat dan logam toksik juga dikenalpastikan. Faktor perbezaan kepekatan telah dibincangkan dalam kajian. Abstract. Determination of trace elements in agriculture soil are to understand and increase soil quality and crop yields as the aim of this study is to etermine the profile and distribution patterns of

fertilizer samples. X-ray fluorescence spectrometry (XRF) were sed to determine trace elements in these study. An X-ray fluorescence method is an alternative multi-

oncentration from levels often below mgkg , up to 100%. Samples were prepared after following ay of drying, refinement, pressing into pellets form, counting and analysis. The concentration of 16

(As, Ba, Ce, Co, Cr, Ga, Hf, La, Nb, Pb, Sr, Th, U, V, Y and Zr) elements were determined quantitatively and qualitatively, which were collected from agriculture area located in the Perlis. Generally, the concentration give a even distribution patterns almost in every samples. Concentration of Ba show large differentiation range from 49ppm to 1617ppm. The concentrations of Ce (22-575ppm), Co (1.4-36ppm), Cr (0.3-23ppm), Pb (17-321ppm) and Th (24-196ppm) in samples were determined. The heavy metal elements were identified. Factors of elemental pattern were also discussed . Kata kunci: tanih sawah, baja, Analisis Pendarfluor Sinar-X (XRF) Pengenalan Sejak manusia menjadi dia mula menaruh perhatian terhadap tanah dan hidupnya juga mula bergantung kepadanya. Sebagai p an tanah

ang lebih luas dan lebih produk mbahkan engetahuannya mengenai bahantara dan cara pembentukannya. Konsep tanah sebagai bahantara yang erguna

anr-unsur-unsur dalam tanih dan baja ditentukan dengan menggunakan teknik Analisis Pend

X (XRF). XRF merupakan teknik instrumentasi tidak memusnah yang berkebolehan

dtrace elements in the both soil and uelement analytical tool for the routine non-destructive analysis over several orders of magnitude

-1cw

petani, etani, manusia terutamanya mementingkan cara penggunatif, iaitu satu keadaan yang tercapai hanya dengan menay

pb dan produktif untuk tanaman telah dihuraikan sebagai ‘tanah sebagai suatu sumber’ [1].

Padi merupakan makanan penting bagi negara-negara Asia terutamanya di negara-negara Asia Tenggara. Laporan menunjukkan China merupakan pengeluar 1/3 daripada jumlah pengeluaran padi sedunia. Sewajar dengan ilham oleh Perdana Menteri Malaysia YAB Dato’ Seri Abdullah Ahmad Badawi untuk memajukan negara dalam bidang pertanian, serta menampung keperluan pada masa hadapan. Perusahaan yang banyak telah dijalankan dalam bidang pertanian ini. Dalam Bajet Malaysia

2005 yang baru-baru ini juga telah memberikan peruntukan RM 1.5 bilion bagi projek pertanian terutamanya kepada projek pekebun kecil. Peruntukan sebanyak RM 300 juta pula sebagai modal permula

erkembangan industri dan pencemaran [7,8]. Perhatian telah diberikan kepada padi tanaman, tanih dan baja yang digunakan. Kesan unsur-unsur surih tersebut diambil berat serta kajian ini dijalankan untuk menentukan kandungan unsur yang hadir. Tanah dan baja merupakan faktor penting dalam pengagihan unsur-unsur surih tersebut. Tanih merupakan kunci komponen bagi ekosistem terestrial samada semula jadi atau dalam pertanian. Tanih menjadi keperluan asas untuk pertumbuhan dan tumbesaran tumbuhan, mereput dan kitar semula bahan jisim yang mati. Tanih mengandungi pelbagai jenis kandungan unsur logam berat dan unsur nadir bumi yang lain. Tanih yang dikaji ini merupakan tanih sawah padi di kawasan negeri Perlis. Kandungan logam berat pada tanih kemungkinan diserap oleh tumbuhan padi, hasil penuaian padi dijadikan beras, makanan manusia seharian. Kandungan pada baja dan tanih juga dikenalpasti dan banyak dikaji kerana prihatin kepada

etodologi

Sampel-sampel tanih dan baja dari kawasan tanih sawah padi Perlis telah dipilih dan dikumpul untuk

ampel yang telah dihaluskan tersebut akan ditimbang dengan berat sampel ±1g dan berat serbuk asid orik ±6g, kemudian acuan campuran ditekan dalam bentuk pellet setelah siap. Bentuk pellet tersebut

alisis oleh pengesan pendarflour sinar-x. Keputusan yang dibilang adalah dalam nilai ppm.

asil keputusan daripada Jadual 3 dan 4 menunjukkan kepekatan unsur Ba berada pada tahap antara ppm, tetapi sampel A1KB2, A1KG2, E1KS2 dan E1KSBT1 pula memberikan nilai

epekatan unsur Ba yang agak tinggi berbanding dengan yang lain. Semua kepekatan Ba mengikut

Rajah 1 tersebut besar bezanya yang ketara dalam tapak sawah dengan tapak sawah walaupun berasal dalam satu kampung yang sama. Keadaan yang sama berlaku pada A1KG, A1KT dan E1KPKB untuk kepekatan unsur Ce. Taburan kepekatan Ce secara keseluruhannya berada dalam lingkungan 22 – 575 ppm dengan purata kepekatan pada 245 ppm. Keseluruhannya

ketara

lokasi y

an bagi mengkomersialkan produk pertanian. Hala tuju kerajaan ini adalah untuk menjadikan Malaysia sebagai pengeluar global yang kompetitif bagi produk pertanian berkualiti tinggi, selamat dan memenuhi piawaian antarabangsa.

Tanah mengandungi pelbagai jenis kandungan seperti unsur logam berat, unsur logam toksik dan unsur nadir bumi yang lain. Namun, seperti sesetengah unsur logam berat dan logam toksik adalah berpotensi berbahaya kepada kesihatan manusia jika melebihi julat tahapnya walaupun pada jumlah yang sedikit [2,3,4,5,6]. Kebanyakan toksik dalam badan biosistem manusia berasal daripada pertumbuhan dan p

persekitaran memandangkan daripada penambahan penggunaan baja jenis organik. XRF, sinar-x pendarfluor juga banyak digunakan dalam penentuan unsur-unsur surih di mana

ia merupakan kaedah analisis unsur-unsur dengan mengenal unsur dan menentu kepekatan pelbagai unsur dalam sampel dengan mengukur keamatan tenaga sesuatu sinar-x yang dapat dilepaskan kepada pembilang. Keamatan tenaga sesuatu sinar-x adalah berkadar dengan kepekatan unsur dalam sampel berkenaan [9,10]. M

kajian penganalisis unsur. Pengumpulan sampel-sampel tanih dan baja tersebut telah dibantu dan kerjasama dari pihak MADA (Lembaga Kemajuan Pertanian MUDA) dan Pertubuhan Peladang kawasan (PPK). Tiga sampel dikumpul dari satu lokasi kampung yang sama. Kesemua 24 sampel tanih (dari lapan kampung yang berada dalam tiga daerah berlainan masing-masing) yang dikumpul telah dikering dan dihalus. Semua sampel yang dianalisis dalam kajian ini telah disenaraikan dalam JADUAL mengikut label, lokasi dan nilai pH. Pelabelan sampel adalah mengikut lokasi daerah seperti Rajah 1 yang disertakan. Sbdilabel dan dian

Hasil dan Perbincangan H500–1000 klokasi kampung pula bertabur dengan sekata kecuali pada lokasi A1KG dan E1KS. Merujuk kepada

, kepekatan Ba dalam lokasi

penaburan kepekatan Ce adalah tidak sekata pada semua lokasi kampung kecuali yang paling pada kawasan E1KPKB, A1KG dan A1KT. Kepekatan unsur naik turun dengan ketara pada kawasan

ang sama.

Rajah 1. Lokasi kawasan pengumpulan sampel

Jadual 1. Pelabelan sampel bagi tanih SAMPEL LOKASI (DAERAH) LOKASI (KAMPUNG) pH A1KT1 Arau Kampung Teluk 4.52 A1KT2 5.74 A1KT3 5.97 A1KB1 Kampung Banat 6.57 A1KB2 5.72 A1KB3 5.64 A1KG1 Kampung Gobek 5.44 A1KG2 5.22 A1KG3 5.31 D1KTTT1 Tambun Tulang Kampung Tambun Tulang Timur 5.02 D1KTTT2 4.53 D1KTTT3 3.85 D1KLJ1 Kampung Lahar Jambu 5.00 D1KLJ2 4.90 D1KLJ3 5.54 E1KS1 Simpang Empat Kampung Kuala Sanglang 6.44 E1KS2 6.26 E1KS3 6.57 E1KPKB1 Kampung Pauh Kepala Batas 5.81 E1KPKB2 6.24 E1KPKB3 6.84 E1KSBT1 Kampung Sungai Baru Timur 6.00 E1KSBT2 5.49 E1KSBT3 5.87

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Rajah 4 (a) (b). Kepekatan unsur untuk sampel baja

Kepekatan unsur pada baja melihat juga terdapat ketidakserataan seperti tunjukkan pada Rajah 4. Kepekatan unsur-unsur As, Ba, Ce, Th, V dan Zr telah menunjukkan penaburan unsur yang tidak teratur. Graf menunjukkan kepekatan unsur-unsur tersebut turun-naik dengan mendadak dan tidak seimbangan pembahagi pada baja. Baja UREA 46%N menunjukkan mempunyai kepekatan unsur V dan Zr yang rendah berbanding dengan sampel baja lain, tetapi memberikan kepekatan yang

sebalik untuk unsur As, Ce dan Th. Baja Padi Tambahan lembing Sakti pula memberikan kepekatan unsur Ba yang jauh lebih tinggi dalam antara sampel baja tersebut.

Pemerhatian penaburan yang tidak sekata serta sesetengah kepekatan unsur yang tinggi kemungkinan disebabkan oleh perbezaan nilai pH yang telah mempengaruhi kandungan nutrient yang terdapat dalam tanih. Mengikut Bear [11] analisis tanih untuk jumlah kuantiti bagi sesetengah unsur yang jumpa dalam tanih memberikan variasi yang banyak. Ia bergantung bukan sahaja kepada keadaan batuan semula jadi yang membentuk tanih tersebut, tetapi juga bergantung kepada umur tanih tersebut dan keupayaan ia melarutkan air. Walaupun kawasan tersebut mempunyai jumlah hujan, suhu, batuan dan mineral asal yang sama, tetapi tiada pun dua tanih yang mempunyai kandungan kimia yang sama.

Faktor lain dalam pengaruhan sifat kandungan adalah kemungkinan faktor geologi kawasan tanih tersebut. Pemilihan kawasan kajian adalah kawasan A1 di sebelah dalaman yang mendekati dengan kawasan penggunungan dan sumber penghiliran air serta kawasan E1 pula merupakan

awasan tepi dan berhampiran dengan laut, manakala kawasan D1 merupakan kawasan pertengahan k di antara kawasan pedalaman dan tepi laut. Perbandingan menunjukkan taburan

epekatan unsur pada kawasan A1 dan E1 sememangnya banyak yang tidak sekata berbanding ang taburan kepekatan unsur lebih sekata. Kebarangkalian perbezaan kepekatan

unsur adalah tinggi. Perbezaan taburan kepekatan unsur yang ketara dapat dilihat daripada graf taburan kepekatan unsur Ba dan Ce keseluruhan.

Penyerapan unsur-unsur oleh tumbuhan banyak dipengaruhi oleh faktor geokimia pada tanih tersebut, terutama pada komponen dan kandungan mineral yang terdapat dalam tanih [12]. Sifat kimia tanih dan kesan penggunaan baja juga boleh memberi kesan kepada kandungan kepekatan unsur-unsur. Mengikut Coker [13] dan Kalpagé [14] pembajaan tanih biasa digunakan untuk mengekalkan dan meningkatkan kualiti tanih tersebut serta meningkatkan penghasilan dan kualiti tanaman, tetapi jika tidak digunakan dengan wajar sekali akan mengakibatkan kesan negatif untuk haiwan dan keselamatan manusia. Kesimpulan Dalam penyelidikan ini, penentuan unsur-unsur surih dalam tanih dan baja secara analisis pendarflour sinar-X (XRF) telah dapat menentukan dengan kesemuanya 16 unsur. Unsur-unsur tersebut telah dikumpulkan kepada unsur NORM (U, TH) dan unsur REE (Ce dan La) serta unsur berat bertoksik (As, Ba, Co, Cr, Ga, Hf, Nb, Pb, Sr, V, Y dan Zr). Data telah dianalisis dengan kepekatan yang terkandung dan dapat memperbaiki dan membaikpulihkan sifat tanih tersebut serta data digunakan

.M., Zohny, E. (2001) “Heavy Metal and Rare ponents Using Instrumental Neutron Activation

plied Radiation and Isotopes 55. 569-573.

kyang terletakdengan kawasan D1 y

untuk kajian selanjutnya. Nilai data ini akan digunakan membuat perbandingan dengan kaedah Analisis Pengaktifan neutron Instrumentasi (APNI). Penghargaan Penulis ingin memberi penghargaan atas bantuan dan kerjasama daripada pihak MADA (Lembaga Kemajuan Pertanian MUDA) dan Pertubuhan Peladang kawasan (PPK) yang mengumpul sampel-sampel. Rujukan 1. Cruickshank, J.G. (1983) “Geografi Tanah-Tanih”, Ismail B. Ahmad (pnjh). Kuala Lumpur:

Dewan Bahasa dan Pustaka. 2. Abdel-Haleem, A.S., Sroor, A., El-Bahi, S

Earth Elements in Phosphate Fertilizer ComAnalysis”, J. Ap

3. Alloway, B.J. (1990) “Heavy Metal in Soils”, Glasgow & London: Blackie & Sdn.Ltd. 4. Smith, D.G. (1986) “Heavy Metals in the New Zealand Aquatic Environment. A Review Water

& Soil Directorate”, New Zealand: Wonistry of Works & Development.

5. Ahmad, S., Chaudhary, M.S., Mannan, A., Qureshi, I.H. (1982) “Determination of Toxic Elements in Tea Leaves by Instrumental Neutron Activation Analysis”, J. Radioanalytical and Nuclear Chemistry 78. 375-383.

6. Frederick, W.O. (1978) “Toxicity of Heavy Metals in Environment”, New York: Marcel Dekler Inc.

M. Abdel-Wahab, A. Sroor, A.S. Abdel-Haleem, M.F. Abdel-Sabour. (1999)

0. Wilkins, Carolyn. (1983) “X-Ray Fluorescence Analysis”, dlm: Smith, Keith A. (pnyt). Soil Analysis- Instrumental Techniques and Related Procedures. New York: Marcel Dekker, Inc. 195-225.

11. Bear, Firman E. (1977) “Soils in Relation to Crop Growth”, New York: Robert E. Krieger Publishing Company.

12. Wang, Y. Q., Sun, J. X., Chen, H. M., Guo, F. Q. (1997) “Determination of the Contents and Distribution Characteristics of REE in Natural Plants by NAA”, J.Radioanalytical and Nuclear Chemistry 1. 219. 99-103.

13. Coker, E.G. (1971) “Horticultural Science & Soils- Volume 2: Soils & Fertilisers”, London Macdonald Technical & Scientific.

14. Kalpagé, F.S.C.P. (1979) “Soils and Fertilizers for Plantations in Malaysia”, Kuala Lumpur: Kuala Lumpur Incorporated Society of Planters.

7. Nada, A.,“Heavy Metals and Rare Earth Elements Source-Sink in Some Egyptian Cigarettes as Determined by Neutron Activation Analysis”, J. Applied Radiation and Isotopes 51. 131-136.

8. Pollock, Eugene N. (1974) “Trace Impurities in Coal by Wet Chemical Methodsz”, dlm: Babu, Suresh P. (pnyt). Trace Element in Fuel. (Advances in Chemistry Series 141).. Washington, D.C.: American Chemical Society. 23-34.

9. Hamzah Mohamad. (2002) “Spektrometri Sinar-X”, nota kuliah. Bangi: Jabatan Geologi. Universiti Kebangsaan Malaysia.

1

a ek n ur lam sampel tanih (dalam ppdual 3. Kep ata Uns -unsur da m) Sampel Kepekatan Unsur (ppm) Ba Ce La U Th Cr V Nb Zr Y Sr Pb As Ga Hf Co A1KB1 8 5 6 46 21.640 33.9 4.08 27 20.360 58.006 99.698 1.132 20.273 10.090 885.47 3 5.49 69.4 85 5 99.4 33.662 A1KB2 81 30 6 29 18.126 66.1 3.92 85.919 26.198 12.4 38.376 60.346 1.465 20.247 10.640 36.638 A1KB3 55 6 160 27.308 49.1 6.44 96.137 22.838 24.5 38.899 11 37.248 3.625 20.802 8.438 A1KG1 7 0 11 23.907 131. 12.7 102.371 15.740 9 38 54.785 3.417 20.857 7.061 15.104 A1KG2 4 5. 552 29.859 80.38 0.30 120.381 20.528 6 88 33.826 4.747 20.795 8.576 19.998 A1KG3 5 916 19.032 163. 0.93 104.449 17.336 1 07 23.988 8.029 20.700 6.924 A1KT1 2 2. 29.632 94.66 1.25 .505 20.150 12 46.882 105.259 3.708 20.754 6.098 9.231 A1KT2 7 18.182 102.696 4.08 05 20.780 0 53.949 75.317 6.617 20.674 8.300 1.401 A1KT3 2 37 1 26.004 97.342 9.59 .276 13.808 4 28.953 73.178 3.999 20.864 7.612 19.020 D1KLJ1 7 95 21.810 100.019 6.91 .505 20.360 0 23 1. 6 20.692 10. 2.380 D1KLJ2 3 42 20.903 67.894 27 26.871 3 46.097 7.9 9 20.915 8.7 D1KLJ3 5 82 25.551 114.297 3.61 19 23.846 1 76 7. 20.003 6.6 16.083 D1KTTT1 621 21.243 133.929 23.7 41 24.308 3 34.319 2. 20.689 5.685 12.168 D1KTTT2 9 135.673 86.993 23.454 81.280 13. 34 24.812 895 32.356 0. 4 20.707 9.126 6.295 D1KTTT3 9 322.189 264 28.045 196.394 5.815 93.366 20.024 3.127 20.627 9.677 E1KPKB1 328.851 552 26.741 62.540 6.28 98.561 26.619 22.9 49.892 48.797 6.035 20.722 8.576 E1KPKB2 219 95.704 576 22.773 24.169 1.41 95.617 26.955 23.3 39.946 69.756 3.459 20.962 6.235 15.104 E1KPKB3 057 548.674 69 30.482 86.634 2.66 109.644 18.428 28.4 34.973 321.259 2.462 20.809 7.474 23.914 E1KS1 987 163 26.174 109.835 11.6 91.980 26.030 15.990 34.450 1.866 54.785 1.340 20.831 5.685 E1KS2 9.511 442.093 91 25.494 128.575 3.14 93.712 20.360 27.723 38.637 29.976 4.622 20.565 7.612 E1KS3 377 362 203.676 62.656 27.391 17.830 2.695 19.86 50 13.147 E1KSBT1 4.190 62.398 145.370 17.049 79.495 97.695 23.216 14.137 51.724 1.720 0 7 20.9 1 6.295 E1KSBT2 188.963 88.680 25.211 100.019 3.77 95.617 27.165 14.700 46.751 7 0 21.1 8 16.083 E1KSBT3 184 49.075 112.301 20.280 105.373 6.130 97.522 28.887 24.018 56.304 20.7 3 30.765

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Jadual 4. Kepekatan unsur-unsur dalam sampel baja (dalam ppm) Sampel Kepekatan Unsur (ppm) Ba Ce La U Th Cr V Nb Zr Y Sr Pb As Ga Hf Co bc 250 55.736 158.530 26.846 13.053 23.578 12.338 24.303 7.229 11.807 15 19.989 3 24.4 3.584 6.37706.moc 408 122.350 101.503 2.765 164.269 24.097 0.956 23.020 17.044 0. 20.2 0 u 121 455.416 91.379 580.109 4.714 3.143 15.752 4. 84 21.0 7 bpt 8.738 215.608 97.116 10.474 99.127 17.931 14.226 7.508 16.655 22.541 7.988 19.999 5.547 20.977

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PENENTUAN KUALITI AIR TASIK KEJURUTERAAN UKM

KAMPUS BANGI: KE ARAH SISTEM PENGURUSAN SUMBER AIR BERSEPADU

Jabatan Kejuruteraan Awam & Struktur, Fakulti Kejuruteraan 3Pusat Pengajian Sains Sekitaran dan Alam Sekitar, Fakulti Sains & Teknologi

Universiti Kebangsaan Malaysia 43600 UKM BANGI, Selangor Darul Ehsan, Malaysia

Kata kunci: Kualiti air, tasik, UKM, pengurusan, bersepadu

Key words: Water quality, lake, UKM, management, integrated Abstrak. Sistem pengurusan sumber air bersepadu (IWRM) merupakan suatu proses yang mempromosikan pembangunan penyelarasan dan pengurusan air, tanah dan sumber lain yang berkaitan untuk memaksimumkan manfaat ekonomi dan sosial secara seimbang tanpa menjejaskan kelestarian ekosistem. Kajian mengenai kualiti air Tasik Kejuruteraan, UKM Kampus Bangi dijalankan untuk menentukan kualiti air tasik tersebut, membandingkannya dengan nilai Interim Kualiti Air Kebangsaan (INWQS) (JAS, 2001), dan menganggarkan

4 m3/s manakala, kadar aliran keluar adalah 3

kering bagi TSS. Perbezaan bererti p < 0.05 dicerap bagi data antara bagi parameter suhu, DO dan BOD. Semua stesen pensampelan kajian ini didapati mempunyai kualiti air

uitable statistical ality parameters that were measured are pH, temperature, dissolved oxygen (DO),

conductivity, turbidity, total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal-nitrogen, lead and cadmium. Temperature, pH, conductivity, dissolved oxygen and turbidity were measured in situ by using calibrated meters, whilst metal concentrations were determined by using Atomic Absorption Spectrophotometry (AAS). Methods of sampling and water analyses were performed according to recommendations that were outlined by the American Public Health Association (APHA, 1998). On normal days, the inflow and outfow of the lake were estimated to be 0.057 ± 0.024 m3/s inflow and 0.052 ± 0.018 m3/s outflow. The theoritical retention time of the lake water with a mean depth of 1.5 m and area of

Mazlin Bin Mokhtar1, Othman A. Karim2 & Irene Lee Pei Ngo3

1Institut Alam Sekitar dan Pembangunan (LESTARI) 2

nilai Indeks Kualiti Air berdasarkan enam parameter terpilih. Kajian ini juga bertujuan mengenalpasti sumber dan tahap pencemaran air tasik berkenaan. Kesan hari hujan dan hari kering ke atas kualiti air tersebut juga telah dinilai. Parameter yang diukur adalah pH, suhu, oksigen terlarut (DO), konduktiviti, kekeruhan, jumlah pepejal terampai (TSS), permintaan oksigen biokimia (BOD), permintaan oksigen kimia (COD), nitrogen ammonia (NH3-N), plumbum dan kadmium. Parameter suhu, pH, konduktiviti, oksigen terlarut dan kekeruhan diukur secara in situ dengan menggunakan meter yang telah dikalibrasi. Kandungan logam berat ditentukan dengan menggunakan spektrofotometer serapan atom (AAS). Kaedah pensampelan dan analisis dilakukan mengikut garis panduan yang dicadangkan oleh American Public Health Association (APHA, 1998). Pada keadaan biasa, kadar aliran masuk bagi air tasik dianggarkan sebanyak 0.057 ± 0.020.052 ± 0.018 m /s. Secara teori, masa mastautin air tasik dengan kedalaman purata tasik (1.5 m) dan keluasan (18,000 m2) adalah 62.5 ± 37.6 hari. Jumlah anggaran bagi bahan yang diukur yang berada dalam tasik adalah DO (200.88 ± 28.25 kg), TSS (163.78 ± 18.19 kg), NH3-N (12.65 ± 13.90 kg), BOD (41.90 ± 23.95 kg), COD (1605 ± 75 kg), Pb (9.50 ± 0.90 kg) dan Cd (2.81 ± 0.24 kg). Anggaran jumlah berat bahan yang mengalir ke Sungai Langat setiap hari dari tasik ini adalah TSS (27.81 ± 9.29 kg), NH3-N (2.12 ± 0.71 kg), BOD (7.01 ± 2.34 kg), COD (268.9 ± 89.78 kg), Pb (1.59 ± 0.53 kg) dan Cd (0.47 ± 0.15 kg). Hasil ujian ANOVA dua hala menunjukkan perbezaan yang sangat bererti (p<0.001) antara kepekatan parameter semasa hari hujan dan kering bagi Pb, p < 0.05 antara hari hujan dan stesenKelas II kecuali Stesen S2 yang berada pada Kelas III (sedikit tercemar). Secara keseluruhannya, kualiti air Tasik Kejuruteraan UKM boleh dikategorikan sebagai Kelas II-III. Beberapa langkah yang perlu diambil ke arah sistem pengurusan sumber air bersepadu dalam kampus UKM Bangi bagi mewujudkan kualiti air yang baik, sihat dan harmoni yang selaras dengan tema UKM ‘Universiti dalam Taman’ telah juga dicadangkan. Abstract. Integrated Water Resources Management (IWRM) is a process, which promotes the coordinated development and management of water, land and related resources, in order to maximise the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems. A study on the water quality of the “Engineering Lake”, UKM Bangi Campus was carried out to determine the its water quality, and compare it with the Interim National Water Quality Standard (INWQS) (DOE, 2001), followed by estimation of its Water Quality Index (WQI) based on six selected parameters. The purpose of this study was to identify the possible causes of the water pollution and level of this pollution at the lake. The comparisons of concentration values measured during dry days with those on rainy were performed using smethods. Water qu

18,000 m2 was 62.5 ± 37.6 days. On normal days, the estimated total amounts of materials that were present in the lake were DO (200.88 ± 28.25 kg), TSS (163.78 ± 18.19 kg), NH3-N (12.65 ± 13.90 kg), BOD (41.90 ± 23.95 kg), COD (1605.58 ± 74.68 kg), Pb (9.50 ± 0.90 kg) and Cd (2.81 ± 0.24 kg). The estimated total amount of polluted materials which flowed into the Langat River daily were TSS (27.81 ± 9.29 kg), NH3-N (2.12 ± 0.71

n Future pada tahun 1987 (Bruce, 1997). Pembangunan lestari menekankan pengurusan sumber alam yang terdiri daripada biodiversiti, air, tanah dan sumber lain. Di Malaysia, konsep pembangunan lestari telah dimaktubkan dalam beberapa dasar dan dokumen rasmi kerajaan, seperti Rancangan Jangka Panjang Malaysia Ketiga 2001 – 2010 (“Third Outline Perspective Plan 2001 – 2010), yang merangkumi Rancangan Malaysia ke-8 (2001-2005) dan Rancangan Malaysia ke-9 (2006-2010). Malaysia menyertai Persidangan Pertubuhan Bangsa-bangsa Bersatu mengenai alam sekitar dan pembangunan (UNCED) di Rio de Janeiro, Brazil pada Jun 1992, bila mana konsep pengurusan air secara bersepadu telah dimajukan untuk memastikan bekalan air tawar dunia adalah mencukupi untuk semua penduduk di semua negara bagi tujuan hidupan seharian dan pembangunan lestari. Dalam Millenium Summit of the United Nations di New York (2000), the International Freshwater Conference di Bonn (2001) dan World Summit on Sustainable Development di Johannesburg (2002), peserta dari pelbagai kerajaan, NGO dan organisasi telah digalakkan untuk menyatakan iltizam dalam pengurusan air termasuk untuk menghebahkan dan melaksanakan agenda pendekatan Pengurusan Sumber Air Bersepadu (“Integrated Water Resources Management”, IWRM) (World Water Forum 2003). Global Water Partnership (GWP) atau Pakatan Air Sedunia mendefinisikan IWRM sebagai suatu proses yang mempromosikan pembangunan dan pengurusan sumber air, tanah dan sumber lain yang berkaitan untuk memaksimumkan manfaat ekonomi dan sosial secara seimbang tanpa menjejaskan ekosistem lestari (GWP, 2000b).

berapa skala atau peringkat iaitu kebangsaan, negara, negeri, tempatan atau lembangan sungai. Pengurusan Bersepadu Lembangan Sungai (Integrated River Basin Managemen/ IRBM) merupakan cara pengurusan bersepadu dalam mengatasi pelbagai masalah dan isu sumber air seperti pencemaran air, kekurangan air dan banjir dalam konteks isu guna tanah dan pembangunan di sesebuah lembangan sungai. Lembangan Langat di Semenanjung Malaysia adalah terdiri daripada empat buah daerah, iaitu Hulu Langat, Kuala Langat, dan Sepang di Selangor; serta empat mukim di Negeri Sembilan. Lembangan ini mempunyai keluasan kira-kira 2 940 km2 dan merupakan suatu pusat perindustrian, pembangunan dan pentadbiran di Malaysia yang merangkumi projek nasional seperti Putrajaya, KLIA dan Koridor Raya Multimedia (MSC) (Mazlin et al., 2004). Sungai Langat ini juga mengalir bersebelahan dengan kawasan UKM Kampus Bangi dan sungai ini juga menerima air luahan dari beberapa saluran dan jasad air tertentu dalam kampus tersebut. Satu daripada jasad air tersebut adalah “Tasik Kejuruteraan” UKM yang dinamakan sedemikian kerana kedudukannya yang hampir dengan fakulti tersebut. Tasik ini telah dipilih sebagai kawasan kajian ini memandangkan kualiti airnya yang kelihatan tidak berapa menarik dan juga kerana ia menyumbangkan air luahan kepada Sungai Langat. Permasalahan Kajian

kg), BOD (7.01 ± 2.34 kg), COD (268.9 ± 89.78 kg), Pb (1.59 ± 0.53 kg) and Cd (0.47 ± 0.15 kg). The results from two way ANOVA showed that there were significant differences (p<0.001) between rainy days and dry days for Pb. There were also significant differences (p<0.05) between rainy days and dry days in term of TSS. There were significant differences (p<0.05) between stations in terms of temperature, DO and BOD. All sampling stations were categorized as having Class II water, that means a reasonably good water quality except S2 which was categorized as a Class III, which means it was slightly polluted. On the overall, the Engineering Lake water of UKM Bangi Campus was categorized as Class II-III. Some measures of IWRM were suggested for improvement of the lake’s water quality and its environment, in achieving a healthy lake ecosystem which is in line with UKM’s theme of being a ‘University in A Garden’. Pengenalan

Konsep pembangunan lestari telah dikemukakan oleh World Commission on Environment and Development (Brundtland Commission) dalam laporan Our Commo

IWRM boleh dijalankan dalam be

Pencemaran air telah mula kelihatan berlaku di Tasik Kejuruteraan dan kualiti airnya diandaikan tidak baik berdasarkan pandangan estetik. Antara penyebab pencemaran yang disyaki adalah projek pembinaan Kolej Kediaman Pelajar Kausar dan kompleks Fakulti Teknologi dan Sains Maklumat (FTSM) yang melibatkan kerja pembersihan tanah; serta aktiviti perniagaan di kantin dalam bangunan

Fakulti Kejuruteraan serta blok-blok makmal di sepanjang saluran menuju ke tasik. Kajian kualiti air perlu dijalankan untuk mengenalpasti sumber dan tahap pencemaran air tasik dengan menggunakan parameter fizikal dan kimia. Seterusnya, Indeks Kualiti Air (IKA) bagi kualiti air tasik ini telah juga ditentukan. Objektif Kajian Objektif kajian ini adalah: (1) mengkaji sistem saliran ke Tasik Kejuruteraan, kampus UKM Bangi; (2) menentukan kualiti air pada hari kering dan hari hujan dan kemudian membandingkannya dengan piawaian Interim Kualiti Air Kebangsaan (INWQS) dan piawaian lain yang sesuai untuk menentukan status pencemaran; (3) memberi cadangan tentang langkah-langkah yang perlu diambil untuk mengurangkan pencemaran air dan mengindahkan tasik bagi menghasilkan suasana sihat dan harmoni selaras dengan tema UKM ‘Universiti dalam Taman’ dan juga sebagai inisiatif ke arah pengurusan sumber air bersepadu (IWRM) dalam kampus.

ian Tasik Kejuruteraan ini sebenarnya telah diubahsuai dari sebuah kawasan paya ke tasik buatan manusia pada tahun 1989. Airnya mengalir dari bukit yang berhutan di hulu ke dalam tasik dan air tasik kemudiannya mengalir ke Sungai Langat. Kawasan sekelilingnya telah dikembangkan menjadi taman rekreasi dengan lorong jalan kaki, pondok dan menawarkan aktiviti mengayak untuk pelajar dan warga kampus. Anggaran keluasan Tasik Kejuruteraan ini adalah kira-kira 1.8 hektar. Kedalamannya secara purata adalah 1.5 m. Jabatan Pengurusan Pembangunan (JPP) UKM bertanggungjawab ke atas pengurusan tasik ini dan ia juga bertanggungjawab memantau dan menjaga kebersihan tasik. Kini, pencemaran air telah mula kelihatan dan kualiti air disyaki menjadi semakin teruk. Nilai estetik di tasik kelihatan menurun saban hari dan pemandangan di tasik tidak menyenangkan mata. Punca

encemaran boleh dibahagi kepada pencemar tentu dan pencemar tidak tentu (Krenkel & Novotny 1980). Di Tasik Kejuruteraan, pencemar tentu yang dikenalpasti termasuklah hakisan permukaan

ins Maklumat, kantin dan buangan samada air dari makmal, tandas ata lirkan m gan khas ke tangki kumbahan yang kemudiannya disalirkan perawatan sebelum ia dialirkan ke Sungai La t. A dan hakisan kelodak di sekeliling tasik merupakan pencemar tidak tentu. Kajian kualti air ke atas Tasik Kej ukan di lima lokasi yang telah ditentukan sebagai stesen dual 1). Bahan & Kaedah

arameter-parameter kajian

Lokasi Kaj

p

tanah akibat projek pembinaan Kolej Kausar dan longkang kompleks Fakulti Teknologi dan Sa bangunan Fakulti Kejuruteraan. Menurut JPP, semua air

u kanti kol

n disa oleh paip pen kumbahan UKM untuk proses

bentun kenga

am pengoksiir larian hu

daajan

uruteraan ini dilakpensampelan (Ja

PParameter-parameter yang diukur adalah pH, suhu, oksigen terlarut (DO), konduktiviti, kekeruhan, jumlah pepejal terampai (TSS), permintaan oksigen biokimia (BOD), permintaan oksigen kimia (COD), nitrogen ammonia (NH3-N), plumbum dan kadmium. Parameter suhu, pH, konduktiviti, oksigen terlarut dan kekeruhan diukur secara in situ dengan menggunakan meter yang telah dikalibrasikan. Kandungan logam ditentukan dengan menggunakan spektrofotometer serapan atom (AAS). Kaedah pengawetan dan penyimpanan sampel sebelum analisis adalah seperti yang

oleh APHA (1998). disarankan Secara ringkas, pengukuran suhu, pH, DO, konduktiviti diukur dengan meter oksigen terlarut model YSI 556. Meter turbiditi 2020 berjenama Lamotte digunakan untuk mengukur kekeruhan. TSS ditentukan dengan kaedah APHA 2540D melalui penurasan dan pengeringan pada 103-105 0C. BOD adalah sepertimana saranan Kaedah APHA 5210B kaedah elektrod. COD ditentukan melaui kaedah refluks terbuka APHA 5220B. Nitrogen ammonia diukur dengan kaedah HACH Quick Program 380 (Kaedah Nessler) menggunakan spektrometer HACH DR2000 pada jarak gelombang 425 nm. Halaju aliran air diukur dengan meter aliran elektromagnet model Valeport 801 Ver 3.10.

Jadual 1: Stesen pensampelan dalam kajian ini Stesen Koordinat Perihalan ringkas 1 U 02o55’12.1”

T101 o 46’20.3” Aliran air sungai dari bukit selepas melalui Fakulti Teknologi dan Sains Maklumat.

2 U 02o55’12.4” T101 o 46’23.6”

Perangkap lumpur yang berdekatan dengan makmal dan kantin Fakulti Kejuruteraan.

3 U 02o55’24.0” T101 o 46’24.5”

Kawasan yang menerima aliran air dari longkang

bangunan Fakulti Kejuruteraan. 4 U 02o55’28.4”

T101 o 46’20.7” Di tengah-tengah tasik.

5 U 02o55’28.2” T101 o 46’17.4”

Kawasan aliran keluar air tasik ke Sungai Langat.

Hasil dan Perbincangan

Pengiraan Data Hidrologi

asil ukuran keluasan melintang bagi aliran masuk ialah 0.151 m2 dan aliran keluar ialah 0.092 m2. Kadar aliran isipadu, Q (m3/s)= V × A……..Persamaan(1) di mana V= halaju aliran (m/s), A = keluasan melintang (m2) Kadar aliran isipadu masuk, Qin = Vin × A

= 0.376 m/s × 0.151 m2 = 0.057 ± 0.024 m3/s Kadar aliran isipadu keluar, Qout = Vout × A

= 0.567m/s×0.092 m2 = 0.052 ± 0.018 m3/s

Luahan aliran masuk & keluar, Q = Qin– Qout ……..Persamaan (2)

a

H

Q = 0.057 m3/s – 0.052 m3/s = 5.0 × 10-3 ± 0.003 m3/s Masa mastautin, th = I / Q…..Persamaan(3) di m na I= isipadu tasik (m3), Q= Luahan aliran masuk & keluar (m3/s) Masa mastautin, th = I/ Q = 27,000 m3

-3 3 (5.0 x 10 m /s) = 5.4 x 106 s Jadi, dijangka air tasik berada dalam tasik selama 62.5 ± 37.6 hari. Bagi pengiraan sesuatu pencemar, purata kepekatan di lima stesen diambilkira: Jumlah berat, M = C × I……Persamaan(4)

a

PersamKejuruteraan

di m na C = kepekatan sebatian, I = isipadu air Kadar aliran berat, L = C × Qout .…..Persamaan (5)

aan (5) boleh digunakan untuk menganggar jumlah pencemar yang mengalir dari Tasik ke dalam Sungai Langat.

Parameter-parameter Nilai purata dan sisihan piawai bagi setiap parameter kajian pada pensampelan hari kering dan hari hujan diringkaskan dalam Jadual 2 dan Jadual 3. Suhu

keada n yang bererti di antara stesen dengan p=0.006. Suhu berada dalam julat 28.00 ± 0.01 C hingga 30.84 ± 1.57

pH Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.10) di antara keadaan hari hujan-kering dengan P=0.148. Tiada perbezaan yang bererti (p>0.10) antara stesen dengan P=0.913. Nilai pH stesen kajian berada dalam julat 6.06 ± 0.07 hingga 7.57 ± 1.61, iaitu berada pada subkelas IIA. Berdasarkan INWQS (1998), nilai pH yang melebihi julat 6 hingga 9, menunjukkan pencemaran air telah berlaku. Namun menurut APHA (1992), kebiasaannya nilai pH air yang neutral ialah di antara julat 4 hingga 9. Nilai ini adalah merupakan nilai biasa yang menunjukkan kehadiran ion bikarbonat dan karbonat dalam keadaan alkali dan logam alkali bumi. Nilai pH air semulajadi dipengaruhi oleh bahan organik tanah seperti asid humik, asid tanik, asid uronik dan asid mineral hasil aktiviti tanah (Mokhtar et al., 2003). Konduktiviti Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.10) di antara keadaan hari hujan-kering dengan P=0.339. Tiada perbezaan yang bererti (p> 0.10) antara stesen dengan P=0.712. Julat konduktiviti berada dalam julat 168.33 ± 13.61 µS/cm hingga 207.67 ± 8.14 µS/cm. Menurut Chapman (1992), kondukivitit air permukaan biasanya berada dalam julat 10 µS/cm hingga 1000 µS/cm, tetapi mungkin melebihi nilai julat ini terutamanya dalam air yang tercemar atau sistem saliran yang menerima air larian permukaan. Konduktiviti mengukur bahan bukan organik terlarut yang terion membentuk elektrolit. Konduktiviti dan jumlah pepejal terampai adalah berkadaran terus antara satu sama lain (Mokhtar et al., 2003). Kekeruhan Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.10) di antara keadaan hari hujan-kering dengan P=0.163. Manakala, tiada perbezaan yang bererti (p>0.10) antara stesen dengan P=0.399. Nilai kekeruhan berada dalam julat 12.19 ± 14.56 NTU hingga 192.27 ± 287.48 NTU. Semua stesen berada pada subkelas I kecuali S2 yang melampaui paras maksimum 50 NTU yang disarankan oleh subkelas IIB. Stesen S2 adalah paling keruh (192.27 ± 287.48 NTU) pada hari hujan kerana merupakan perangkap lumpur yang memerangkap sedimen dari projek pembinaan Kolej Kausar dan kompleks FTSM. TSS Analisis statistik ANOVA dua hala menunjukkan terdapat perbezaan yang bererti (P<0.05) di antara keadaan hari hujan-kering dengan P=0.049. Manakala, tiada perbezaan yang bererti antara stesen dengan P=0.527. TSS adalah lebih tinggi pada hari hujan kerana air larian permukaan sewaktu hujan mempunyai daya hakisan yang kuat dan mengakibatkan kadar hakisan tanah yang kuat dan menyumbangkan kepada peningkatan pepejal terampai di kawasan tanah rata terutamanya yang terdedah akibat proses pembangunan. Nilai TSS berada dalam julat 5.33 ± 2.57 mg/L hingga 69.00 ± 92.15 mg/L. Pada hari kering, semua stesen terletak pada subkelas I. Manakala pada hari hujan, semua stesen dikategori sebagai subkelas I kecuali S2 berada pada subkelas III. Stesen S2 mempunyai TSS yang paling tinggi (69.00 ± 92.15 mg/L) pada hari hujan kerana merupakan perangkap lumpur yang memerangkap sedimen dari projek pembinaan Kolej Kausar dan kompleks FTSM. Pada keadaaan normal, jumlah berat TSS dalam tasik adalah 163.78 ± 18.19 kg. Anggaran jumlah pepejal terampai yang mengalir masuk ke Sungai Langat adalah 27.81± 9.29 kg setiap hari. Oksigen Terlarut Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.05) di antara keadaan hari hujan-kering dengan p=0.068. Manakala, terdapat perbezaan yang bererti antara stesen dengan P=0.014. DO berada dalam julat 5.47 ± 1.16 mg/L hingga 8.53 ± 0.80 mg/L. Pada hari kering, semua stesen berada pada subkelas I kecuali S3 berada pada subkelas IIA. Pada hari hujan, S4 dan S5 berada pada subkelas I manakala S1, S2, S3 berada pada subkelas IIA. S3 mempunyai nilai DO yang paling rendah (5.47 ± 1.16 kg) kerana kehadiran bahan organik yang tinggi di S3. Bakteria

Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.05) di antara an hari hujan-kering bagi lima stesen dengan P=0.717. Manakala, terdapat perbezaa

0

0C.

m n normal, dianggarkan 200.88 ± 2 ir tasik.

Nitrogen Ammonia Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.10) di antara keadaan hari hujan-kering d rerti (p>0.10) antara stesen dengan p=0.476. Nilai nitrogen ammonia berada dalam julat 0.08 ± 0.03 mg/L hingga 1.54 ± 0.85 mg/L. Pada hari kering, Stesen S3 terletak dalam subkelas I; S2 dan S3 berada pada subkelas IIA, manakala S5 terletak pada subkelas III dan S4 terletak pada subkelas IV. Pada hari hujan, Stesen S1,

yang bererti (p>0.10) di antara

aan yang bererti (p>0.10)) di antara g bererti (p>0.10) antara stesen dalam kategori subkelas IV (51

00 mg/L) berdasarkan INWQS disebabkan kehadiran bahan organik dan bahan bukan organik yang banyak dalam tasik mungkin disebabkan air larian sisa makanan dari kantin dan air sisa buangan dari makmal dan bengkel fakulti. Menurut JPP, semua air buangan samada air dalam makmal dan tandas disalirkan oleh paip pembetungan dalam sistem pembetungan ke kolam pengoksidaan kumbahan UKM untuk proses perawatan sebelum ia dialirkan ke Sungai Langat, namun terdapat kemungkinan air sisa ini juga mengalir dalam saluran longkang dan mengikut air larian sewaktu

Analisis statistik ANOVA dua hala menunjukkan terdapat perbezaan yang sangat bererti (p<0.001) di antara keadaan hari hujan-kering dengan p=0.001. Julat Pb ialah 0.32 ± 0.06 mg/L hingga 0.40 ± 0.08 mg/L sewaktu hari kering manakala julatnya pada hari hujan adalah 0.12 ± 0.10 mg/L hingga 0.19 ± 0.11 mg/L. Nilai Pb adalah rendah semasa hujan disebabkan proses pencairan air tasik. Tiada

enggunakan oksigen terlarut semasa proses penguraian bahan organik tersebut. Pada keadaa8.25 kg oksigen terlarut berada dalam a

engan P= 0.545. Tiada perbezaan yang be

S3, S4 dan S5 dikategori sebagai subkelas III dan S2 terletak pada subkelas IV. Ini mungkin disebabkan air kumbahan domestik yang dilepaskan ke dalam Tasik Kejuruteraaan dan pembuangan air sisa makanan dari kantin. Menurut Jabatan Pengurusan Pembangunan (JPP), semua air buangan samada air dalam makmal dan tandas disalirkan oleh paip pembetungan dalam sistem pembetungan ke kolam pengoksidaan kumbahan UKM untuk proses perawatan sebelum ia dialirkan ke Sungai Langat, namun dijangkakan terdapat juga luahan air buangan yang disalirkan ke dalam longkang yang akhirnya mengalir ke dalam tasik kajian. Pada keadaaan normal, dianggarkan 12.65 ± 13.90 kg nitrogen ammonia berada dalam tasik. Anggaran jumlah nitrogen ammonia yang mengalir masuk ke Sungai Langat adalah 2.12 ± 0.71 kg setiap hari.

Permintaan Oksigen Biokimia (BOD) Analisis statistik ANOVA dua hala menunjukkan tiada perbezaan keadaan hari hujan-kering dengan p=0.354; manakala, terdapat perbezaan yang bererti antara stesen dengan p=0.018. BOD berada dalam julat 0.49 ± 0.37 mg/L hingga 3.48 ± 2.03 mg/L. Pada hari kering, S1 dan S5 terletak pada subkelas I manakala S2, S3 dan S4 berada pada subkelas IIA. Pada hari hujan, S1 dan S5 terletak pada subkelas I, S3 dan S4 berada pada subkelas IIA, manakala S2 berada pada subkelas III. Stesen 2 mempunyai nilai BOD yang paling tinggi, iaitu 3.48 ± 2.03 mg/L sewaktu hari hujan. Ini mungkin kerana stesen ini terletak berdekatan dengan bengkel fakulti kejuruteraan. Kawasan bengkel ini mungkin menyebabkan saliran air buangan berjaya masuk ke dalam longkang pada hari hujan yang mengandungi bahan berorganik tinggi yang boleh meningkatkan paras kepekatan BOD dalam sistem air. Pada keadaaan normal, jumlah berat BOD yang dianggarkan hadir dalam tasik adalah 41.90 ± 23.95 kg. Anggaran BOD yang mengalir masuk ke Sungai Langat adalah 7.01 ± 2.34 kg setiap hari.

Permintaan Oksigen Kimia (COD) nalisis statistik ANOVA dua hala menunjukkan tiada perbezA

keadaan hari hujan-kering dengan p=0.729. Tiada perbezaan yandengan P=0.955. Secara keseluruhan, nilai COD adalah tinggi, iaitumg/L hingga 1

hari hujan. Nilai COD yang tinggi menunjukkan pembuangan air sisa yang mungkin dialirkan secara langsung atau tidak langsung dari kawasan bangunan fakulti. Pada keadaaan normal, dianggarkan air tasik mengandungi jumlah berat COD sebanyak 1605.58 ± 74.68 kg. Anggaran COD yang mengalir masuk ke Sungai Langat adalah 268.90 ± 89.78 kg setiap hari. Nilai ini adalah amat tinggi dan memberikan beban terhadap kualiti air Sungai Langat yang semakin tercemar.

Plumbum

perbezaan yang bererti antara stesen dengan p=0.345 hasil ujian ANOVA. Secara keseluruhan, nilai Pb adalah amat tinggi dan melebihi had piawai JAS, iaitu 0.05 mg/L. Kebanyakan plumbum yang dibebaskan ke atmosfera berpunca daripada bahan api kenderaan bermotor yang mengandungi bahan kimia antiketuk, tetraetil plumbum, (C2H5)4Pb. Plumbum yang termendap di tempat letak kereta dan jalanraya boleh dibawa oleh air larian permukaan dan mengalir ke dalam tasik. Menurut Camp dan Meserve (1974), berdasarkan pencemaran yang diakibatkan daripada kawasan bandar, terdapat peningkatan masalah kontaminasi logam berat semasa berlakunya air larian permukaan di kawasan bandar. Menurut Spliethoff dan Hemond (1996), kewujudan plumbum bukan sahaja boleh dicerap di kawasan berkepadatan dengan kenderaan, tetapi juga dalam atmosfera yang turun dengan air hujan dan diangkut ke sedimen akuatik dengan berkesan berbanding dari permukaan kawasan pertanian. Pada k

admium k ANOVA dua hala menunjukkan tiada perbezaan yang bererti (p>0.10) di antara

keadaan hari hujan-kering dengan p=0.404. Tiada perbezaan yang bererti (p>0.10) antara stesen dengan P=0.931. Julat Cd ialah 0.09 ± 0.02 mg/L hingga 0.11 ± 0.04 mg/L. Nilai kepekatan Cd adalah amat tinggi dan melebihi had piawai JAS, iaitu 0.01 mg/L. Ini mungkin disebabkan kehadiran Cd dalam debu dan termendap di tasik. Kewujudan Cd dalam atmosfera biasanya berpunca dari pembakaran bahan api dalam kenderaan bermotor, kegiatan perindustrian dan aktiviti pembinaan yang amat pesat di sekitar lembangan. Pada keadaan normal, kandungan Cd dalam tasik dianggarkan 2.81 ± 0.24 kg.

badan. Indeks Kualiti Air (IKA) Jadual 4 menunjukkan nilai IKA secara purata bagi hari hujan dan hari kering di stesen kajian ini.

Jadual 4: Nilai IKA secara purata di stesen kajian ini Stesen IKA Pengelasan Status

eadaaan normal, dianggarkan terdapat kandungan Pb sebanyak 9.50 ± 0.90 kg. Anggaran jumlah Pb yang mengalir masuk ke Sungai Langat adalah 1.59 ± 0.53 kg setiap hari. Nilai ini adalah amat tinggi kerana logam berat ini amat toksik kepada manusia walaupun dalam kuantiti kecil. KAnalisis statisti

Anggaran jumlah Cd yang mengalir masuk ke Sungai Langat adalah 0.47 ± 0.15 kg setiap hari. Nilai ini adalah tinggi dan membahayakan hidupan jika ia terkumpul dalam tisu

1 81.32±3.33 II Baik 2 72.85±2.45 III Sedikit tercemar 3 81.22±0.02 II Baik 4 81.99±3.24 II Baik 5 82.50±2.62 II Baik

Semua stesen pensampelan berada pada Kelas II, iaitu mempunyai kualiti air yang baik kecuali stesen S2 dika

benarkan kegunaannya untuk aktiviti rekreasi yang melibat

an keruh dan berwarna coklat. Cadangan Berikut merupakan cadangan tentang langkah-langkah yang perlu diambil untuk menuju ke arah

RM dalam kampus bagi menghasilkan suasana ekosistem sihat dan harmoni selaras dengan tema UKM ‘Universiti dalam Taman’. Di peringkat kampus, Pembuatan Keputusan Kolaboratif atau ‘Collaborative Decision Making” atau “CDM” (Mazlin et al. 2004b) sangat digalakkan sebagai inisiatif bersama pelbagai pihak berkepentingan termasuk pihak pengurusan tertinggi universiti yang terdiri daripada Naib Canselor, pihak pengurusan profesional dan eksekutif seperti jurutera dan peringkat lain merangkumi warga universiti yang terdiri daripada pengajar, pelajar dan kakitangan sokongan serta pengguna lain seperti kontraktor projek bertujuan untuk memperbaiki sistem pengurusan sumber air yang sedia ada. CDM menggalakkan proses perkongsian dan pertukaran maklumat di antara pelbagai pihak, dan secara tak langsung turut memperbaiki alat sokongan

tegorisebagai Kelas III, iaitu sedikit tercemar dan memerlukan rawatan ekstensif. Secara keseluruhannya, Tasik Kejuruteraan dikategorikan sebagai Kelas II-III, iaitu merupakan bekalan air yang memerlukan rawatan konvensional dan mem

kan sentuhan. Hujan mempengaruhi kualiti air Tasik Kejuruteraan, terutamanya pada musim tengkujuh, yang menyebabkan nilai bagi parameter TSS meningkat dengan banyak dan menyebabkan air tasik kelihat

IW

membua

proses berkongsi data dan maklumat, serta cara menangani isu bersama

lam tasik manakala kontraktor bertanggngjawab dalam pengaliran air uangan berkelodak dan mengandungi pelbagai bahan buangan lain serta perlu juga mereka

menjamin kebersihan air tasik. in i n dan sumber manusia yang berpatutan juga perlu disediakan oleh pihak

pengurusan universiti, bermula dengan menerapkan konsep IWRM dan CDM kepada golongan staf

IIB pada hari kering manakala semua stesen telah melebihi paras aksimum subkelas IIB pada hari hujan. Kandungan BOD di S2 tergolong dalam subkelas III pada

1. AHPA.AWWA.WEF. 1998. Sta ater Ed.20, American Public Health Association, Washington.

2. Bruce Mitcell, 1997. Resource and Environmental Management. England. Wesley Longman Limited.

3. Camp, T.R. & owden Hutchinson & Ross, Inc.

t keputusan. Orang ramai yang memasuki kampus seperti ibu bapa pelajar dan orang yang menggunakan kemudahan universiti juga harus didedahkan tentang konsep CDM dan IWRM. Pihak pengurusan universiti bertanggungjawab membuat dasar dan peraturan, menetapkan mesyuarat bersama. eksekutif dan menggalakkan

. Jurutera atau saintis berperanan dalam pemonitoran kualiti air. Pengajar perlu menerapkan konsep IWRM kepada setiap pelajar. Kakitangan sokongan mesti juga terlibat membantu mengawal pelepasan sisa secara tidak bertanggungjawab. Pelajar harus menjaga kebersihan tasik seperti tidak membuang sampah ke dabmengambil inisiatif untuk Sela tu, dana kewanga

sedia ada. Kakitangan di Jabatan Pengurusan Pembangunan khususnya perlu didedahkan dengan konsep tersebut agar dapat mengurus tasik ini dengan baik. Daya tampung bagi bahan pencemar dalam tasik harus dinilai oleh pihak jurutera. Jenis spesies hidupan yang ada di dalam tasik perlu diketahui melalui kajian masa depan. Pangkalan data harus dibina dan dikongsi bersama oleh semua pihak berkepentingan dalam universiti, dan masyarakat yang berminat.

Kesimpulan Sistem saliran air ke Tasik Kejuruteraan telah dikaji dan menunjukkan bahawa parameter kekeruhan di S2 melampaui paras maksimum 50 NTU yang disarankan oleh subkelas IIB bagi INWQS. Jumlah TSS di S2 tergolong dalam subkelas III pada hari hujan. Parameter NH3-N di S5 dan S4 telah melebihi paras maksimum subkelas mhari hujan. Nilai COD adalah tinggi, iaitu dalam kategori subkelas IV. Nilai kepekatan Pb adalah amat tinggi dan melebihi had piawai JAS, iaitu 0.05 mg/L. Nilai kepekatan Cd adalah amat tinggi dan melebihi had piawai JAS, iaitu 0.01 mg/L. Tasik Kejuruteraan dikategori dalam Kelas II-III bagi INWQS. Analisis ANOVA dan kolerasi telah dilakukan. Beberapa langkah untuk memperbaiki kualiti air dan keadaan saliran air tasik serta sistem sumber air di kampus telah juga dicadangkan. Rujukan

ndard Methods for the Examination of Water and Wastew

Meserve, R.L. 1974. Water and its impurities. Ed. Ke 2. Stroudsburd: D

4. DID. 2000. Urban Stormwater Management Manual for Malaysia (Manual Saliran Mesra Alam Malaysia). Vol 5: Runoff Estimation. KL.

5. DID. 2000. Urban Stormwater Management Manual for Malaysia (Manual Saliran Mesra Alam Malaysia). Vol 8: Retention. KL.

6. Global Water Partnership, 2000b. Integrated water resources management. TAC Background papers, Nomer 4, Stockholm, Sweden.

7. JAS. 2001. INWQS (atas talian) http://www.jas.sains.my/jas/river/interim_2-3c.htm (2 Feb 2005).

8. Mazlin bin Mokhtar, Mohd. Talib Latif, Lee Yook Heng. 2003. Kimia Air. KL.Utusan Publications & Distributors Sdn. Bhd.

9. Mazlin B. Mokhtar, Shaharudin Idrus, Sarah Aziz. 2004. Kesihatan Ekosistem Lembangan Langat. Prosiding Simposium Penyelidikan Ekosistem Lembangan Langat 2003, Penerbit LESTARI, UKM.

10. Mazlin B. Mokhtar, Rahmah Elfithri and Abdul Hadi Harman Shah. 2004b. “Collaborative Decision Making as a Best Practice in Integrated Water Resources Management: A Case Study

on Langat Basin, Malaysia”. Proceedings (Technical Papers), First Southeast Asia Water Forum, 17-21 November 2003, Chiang Mai, Thailand, Volume 2: pp. 333-354. ISBN 974-241-776-8.

11. World Water Forum 2003 (atas talian) http://www.water-forum3.com (21 Oktober2004). 12. Spliethoff, H.M. & Hemond, H.F. 1996. History of toxic dischange to surface waters of the

Aberjona Watershed. Journal of Environmental Science & Technology 30(1): 121-127.

REMOVAL OF BASIC AND REACTIVE DYES: A COMPARISON OF SORPTION AND PHOTODEGRADATION STUDY

S.T. Ong, C. K. Lee and Z. Zainal

Chemistry Department, Faculty of Science,

Universiti Putra Malaysia, 43400 UPM, Selangor, Malaysia. e-mail: [email protected]

Abstract. A comparative study on the effectiveness of using ethylenediamine modified rice hull

RH) and titanium dioxide (TiO2) under ultraviolet irradiation to remove both basic and reactive d

eactive Orange 16 (RO16) by MRH were studied under various experimental conditions. Studies on the sorption of both dyes showed that sorption was pH and concentration dependent. Langmuir

apacities calculated from the Langmuir model are 3.29 and 24.88 mg/g for BB3 and RO16, respectively. The

contact with lorized at

illumination time of 5 hours. The decolorizing efficiency decreased with increasing dye concentration nd a higher efficiency was obtained under solar light illumination.

adi terubahsuai etilenadiamina (MRH) dan titanium dioksida (TiO2) di bawah penyinaran ultraungu bagi

gkirkan kedua-dua pewarna basik dan reaktif daripada larutan akues telah dijalankan. Sifat-bawah pelbagai erapan adalah

dipengaruhi oleh pH dan kepekatan. Persamaan Langmuir telah diaplikasikan untuk memodel sifat pan oleh MRH. Kapasiti erapan maksimum dikira daripada model Langmuir adalah masing–

er cahaya telah 50 mg/l telah

didegradasikan sepenuhnya selepas 6 jam dengan kontak TiO2 di bawah penyinaran UV manakala engan kepekatan yang sama telah dilunturkan warna sepenuhnya selepas diiluminasikan

an pewarna dan

tive dyes; Basic dyes; Sorption; Photodegradation

ntroduction The widespread usage of dyes in many industries has led to a tremendous increase in the production of colored wastes. It is well known that colored waste has a strong impact on the ecosystem and will lead to disturbances to aquatic life. Hence, the environmental issues surrounding the removal of color

, conventional biological treatment methods are ineffective for decolorizing such waste water [1].

e dyes that are o noteworthy he removal of

many organic contaminants which are biologically resistant [2]. However activated carbon is costly nd difficult to regenerate. Thus, there has been intensive research exploring the potential of lternative low-cost materials as sorbents for dyes.

Biological waste materials such as peanut hull, sugarcane dust, saw dust, corn corb, barley husk and rice hull have been studied as alternatives for activated carbon in the removal of dyes in textile wastewater [3-7]. Most of the materials investigated are efficient in binding either basic or

(Mdyes from aqueous solutions was carried out. The sorption characteristics of Basic Blue 3 (BB3) anR

equation was employed to model the sorption behavior of MRH. Maximum sorption c

effect of initial concentrations as well as light source was carried out in the photodegradation of BB3 and RO16. BB3 with concentration of 50 mg/l was totally degraded after 6 hours of TiO2 under UV illumination whereas RO16 at the same concentration was completely deco

a Abstrak. Satu kajian perbandingan terhadap keberkesanan menggunakan sekam p

menyinsifat erapan basik biru 3 (BB3) dan reaktif oren 16 (RO16) oleh MRH telah dikaji di keadaan eksperimen. Kajian erapan terhadap kedua-dua pewarna menunjukkan

eramasing 3.29 dan 24.88 mg/g bagi BB3 dan RO16. Kesan kepekatan dan juga sumbdijalankan ke atas fotodegradasi BB3 dan RO16. BB3 dengan kepekatan

RO16 dselama 5 jam. Keberkesanan pelunturan warna menurun dengan peningkatan kepekateffisiensi yang lebih tinggi diperolehi di bawah illuminasi solar.

Keywords : Reac I

in effluents has become a great concern. Owing to the nature of synthetic dyes

There is thus a need to search for new and economical process that could removcommonly used in the industry. Adsorption and photocatalytic degradation are twtreatment processes. Activated carbon is perhaps the most widely used adsorbent for t

aa

reactive dyes but not both. As they do commonly exist together in wastewater it is of great interest to have a material that can remove both types of dyes at the same time.

Photocatalytic oxidation of pollutants, especially organic pollutants has generated much interest. In this regard, much attention has been focused on one of the most commonly used photocatalyst, titanium dioxide (TiO2). Investigation of photocatalytic degradation using TiO2 has gained considerable interest not only because it is comparatively cheap, but also due to its absence of toxicity. As TiO2 is illuminated by light rays with wavelength below 380 nm, electron-hole pairs are generated. The valence band holes will react with water molecules or hydroxide ions (OH-) to produce hydroxyl radicals (·OH). Both hydroxyl radicals and valence band holes are powerful

xidizing species that will oxidize the organic pollutants to carbon dioxide, water and some simple acids [8]. Oxygen is usually supplied as electron acceptor to prolong the recombination of electron-hole pairs during photocatalytic oxidation [9].

omparative study on the removal of both basic and reactive dyes using two methods: sorption using lenediamine (EDA) modified rice hull (MRH) and photodegradation using TiO2.

tes in this study. Standard dye solutions of 2000 mg/l were repared and subsequently diluted when necessary.

2.2 Sorption experiments All the batch experiments were carried out in duplicate and the results given are the averages. A control without sorbent was simultaneously carried out to ascertain that the sorption was by MRH and not by the wall of the container. Sorption experiments were performed by agitating 0.05 g of sorbent in 20 ml of 100 mg/l dye solution at their natural pH of 4.7 for BB3, 6.0 for RO16 and 5.5 for binary solution in a centrifuge tube at 150 rpm at room temperature (25 +

o

A series of studies have reported that TiO2 photocatalysis is an effective method forecolorizing and oxidizing organic dyes in wastewater [10-14]. The present paper describes ad

cethy Experimental 2.1 Materials Rice hull was washed several times to ensure the removal of dust and ash. It was then rinsed several times with distilled water and dried overnight in an oven at 50 °C. The dried rice hull was ground to pass through a 1 mm sieve and labeled as natural rice hull (NRH). Modification was carried out by treating NRH with EDA in a ratio of 1.00 g rice hull to 0.02 mole of EDA in a well-stirred water bath at 80 oC for 2 hours.

The TiO2 powder P-25 (mainly in anatase form, mean particle size of 30 nm, BET surface area of 50 m2/g) from Degussa (Frankfurt, Germany) was used as the photocatalyst. Basic Blue 3 (BB3, Sigma, 40 % dye content) and Reactive Orange 16 (RO16, Aldrich, 50 % dye ontent) were selected as the sorbac

p

2 oC). The sorbent-sorbate mixture was then centrifuged at 3.0 x 103 rpm for phase separation and the dye concentration of the supernatant was analyzed using Shimadzu 160B double beam UV-vis spectrophotometer. All measurements were made at the wavelengths corresponding to maximum absorption; for BB3, λmax = 654 nm and for RO16, λmax = 494 nm.

To study the effect of pH, a series of 100 mg/l dye solutions of BB3 and RO16 were prepared. The pH of the dye solutions was adjusted to the range of 2 to 10 by adding dilute HCI or NaOH. Each dye solution was shaken with MRH for 4 hours.

The effect of initial concentration was studied by varying the dye concentration from 50 to 100 mg/l for both dyes. At predetermined intervals samples were withdrawn and analyzed for dye concentration.

Sorption isotherms were obtained by agitating samples of sorbent using dye concentrations of 5 to 150 mg/l. 2.3 Photodegradation experiments Irradiation experiments of dye solutions were carried out by stirring 500 ml of 100 mg/l dye solutions at their natural pH in a 1000 ml beaker with 1.25 g of TiO2 at room temperature (25 + 2 oC) for 8 hours unless otherwise stated. Aeration was provided by bubbling air into the reaction solution by an air pump to ensure a constant supply of oxygen. UV-irradiation was provided by a high pressure mercury lamp. At given intervals of irradiation, approximately 5 ml of the solution was withdrawn from the reservoir. The solution was then filtered through a 0.45 µm membrane filter (Milipore) to remove trace of TiO2 particles.

To study the effect of initial concentration and contact time, all the conditions described above apply except the initial concentrations. The initial concentrations were varied from 50 to 100 mg/l for both dye solutions. At predetermined time intervals the mixtures were removed, filtered and analyzed for their dye concentrations.

The effect of different light source was studied by using four different light sources namely white fluorescent light (18 watt), halogen lamp, UV lamp and sunlight between 11.00 to 3.00 p.m. The experiments were conducted by removing 5 ml of dye solutions from the beaker at predetermined time intervals for analysis. Results And Discussion 3.1 Sorption studies 3.1.1 Effect of pH The effect of pH on the uptake of BB3 and RO16 by MRH in both single and binary dye solution is shown in Figure 1. For BB3 in single dye solution, the percentage uptake increased from 1.32 to 66.99 % with increase in pH from 2 to 10. It is suggested that, at low pH, the carboxyl groups on the surface of rice hull that are responsible for binding with BB3 are predominantly protonated (-COOH), hence incapable of binding BB3. With increasing pH, the number of positively charged sites decreases and the number of negatively charged sites increases. This phenomenon favors the sorption of positively charged dye due to electrostatic attraction [15]. The reverse trend was observed in the removal of RO16 where the percentage of uptake was much higher at lower pH. This is because at low pH, the amine groups on the surface of MRH are protonated (–NH4

+), thereby increasing electrostatic attractions between negatively charged dye anions and positively charged sorption sites resulting in an increase in dye sorption [16,17]. Similar observations were obtained in binary dye solutions where uptake was higher. 3.1.2 Effect of initial concentration and contact time The rate of sorption of BB3 and RO16 in single dye solution by MRH as a function of initial concentration is shown in Figure 2. The uptake follows the typical sorption pattern shown by most of the biosorbent, where the initial uptake was rapid followed by a more gradual process, irrespective of the initial dye concentration. In the binary system, there was a noticeable and sudden increase in sorption of RO16 at around 240 min intervals, indicating that there might be more than one step involved in the sorption process. In order to explore the kinetics involved in dye sorption, the experimental data were examined using different equations [18,19]:

303.2)log()log( 1tkqqq ete −=− (pseudo first-order) (1)

and

et qt

hqt

+=1

(pseudo second-order) (2)

where qe = the amount of dyes sorbed at equilibrium (mg/g), qt = the amount of dyes sorbed at time, t (mg/g), k1= the rate constant of pseudo first-order sorption (1/min), h = (k2qe

2 ) = the initial sorption rate (mg/g min) and k2= the rate constant of pseudo second- order kinetics (g/mg min). The rate constants and correlation coefficients for these two sorption kinetics are listed in Table 1. In many studies, the kinetics of sorption by biological materials are described by the first order Lagergren equation. However, it has been shown that, pseudo second-order provides a better fit than the first- order Lagergren model [20]. In this study, it was found that the equilibrium sorption capacities alculated by using the second-order kinetic model gave closer values with those determined

experimentally (Table 1). The correlation coefficients for the second kinetic model obtained at various

c

concentrations are in general higher than those of the first-order equation. This indicates that pseudo second-order kinetics could better explain the data obtained and implies that the rate limiting step may be chemical sorption or chemisorption involving valency forces through sharing or exchange of electron between sorbent and sorbate [19].

0

20

40

60

0 2 4 6 8 10 12

% U

ptak

e

80

100

120

pH

BB3- singleRO16- singleBB3- binaryRO16- binary

Figure 1: Effect of pH on the sorption of BB3 and RO16 in single and binary dye solutions by MRH

0

20

40

60

80

100

0 60 120 180 240 300 360 420 480

Time (min)

% U

ptak

e

BB3- 50 mg/l BB3- 75 mg/l BB3- 100 mg/l

RO16- 50 mg/l RO16- 75 mg/l RO16- 100mg/l

igure 2: Effect of initial concentration and contact time on BB3 and RO16 sorption from single dye

solution by MRH F

3.1.3 Sorption Isotherm Several sorption isotherms have proven useful in understanding the process of sorption. The simplest isotherm is attributed to a pioneer in the study of surface processes, Langmuir, and is called the Langmuir isotherm. The linearised Langmuir equation can be written as

**1

NC

bNNC e

e

e += (3)

here C = equilibrium concentration of the dye (mg/l), N = amount of dye sow e e rbed at equilibrium g/g), N* = maximum sorption capacity (mg/g), b = constant related to the energy of the sorbent (m

(l/mg). The linear plots of Ce/Ne versus Ce obtained from the sorption data for both single and binary dyes by MRH indicate the applicability of Langmuir isotherm. The constants derived from the equations are shown in Table 2. In the binary solution, the maximum sorption capacities, N* of BB3 and RO16 were enchanced by 4.5 and 2.4 times, respectively. The actual mechanism involved in this

sical

more herm

Table nd binary dye solutions

Dye Initial Pseudo first order Pseudo second order Experimental

R sorption R sorption

BB3 .9654 2.233 0.9997 2.232 (single) 75 1.387 0.9510 3.683 0.9940 3.152 100 2.182 0.9576 3.162 0.9936 3.564 RO16 50 9.979 0.8786 12.626 0.9954 11.520 (single) 75 12.465 0.9857 15.244 0.9849 14.956 100 13.960 0.9663 16.835 0.9824 16.904

BB3 (bina 0.9444 9.320 0.9911 8.956 100 8.855 0.8814 11.442 0.9765 10.924 RO16 50 12.882 0.9971 17.271 0.9946 15.272

Table

Langmuir constants

synergistic effect is not clear. However, fitting the model to the sorption process does not necessarily imply any phy

interpretation attached to them since the biosorbent’s surface is non-homogeneous and there could be than one type of sorption sites on the biosorbent’s surface [21]. Nevertheless, this isot

model provides some valuable insight on the maximum sorption capacities of the sorbent studied.

1: Pseudo first and second order constants for the sorption of single a

concentration sorption 2 2

capacities capacities capacities (mg/l) (mg/g) (mg/g) (mg/g)

50 0.550 0

50 4.333 0.9288 6.650 0.9875 6.548 ry) 75 6.434

(binary) 75 22.320 0.9759 28.249 0.9898 25.600 100 23.988 0.9762 31.153 0.9837 29.054

2: Langmuir constants for the sorption of single and binary dye solutions

R 6 0.099 0.991

R 0.028 0.995

3.2 Photodegradation studies 3.2.1 Effect of initial concentration and contact time The photodegradation rate of both dyes in single and binary system decreased with increasing initial concentration. Similar findings have been reported [9, 22]. BB3 with concentration of 50 mg/l was

Dye N*(mg/g) b (l/mg) R2

BB3 3.286 0.102 0.956 O16 24.87

BB3 (binary) 14.680 0.003 0.941 O16 (binary) 60.241

totally degraded after 6 hours of contact with TiO2 under UV illumination. RO16 at the same concentration was completely decolorized at illumination time of 5 hours (Figure 3). As for the binary systems, the formation of residues was observed at the end of the photodegradation

rreportdata u

expe iment. The degradation of various organic contaminants over illuminated TiO2 has been ed to conform to the Langmuir- Hinshelwood first order kinetics model (23). Re-plotting the sing the equation ln (C/Co) versus Time (Figure 4), it is clear that photodegradation of BB3 and

RO16 also follows the pseudo first-order kinetics

ktCCIn o = (4)

3.2.2 Figure 5 shows the comparison of color removal efficiency of single BB3 and RO16 with various light sources. Different light sources have different wavelength ranges and if the provided light source has a wavelength shorter than 400 nm or equivalent energy higher than 3.2 eV, it can photoexcite TiO2 and produce electron-hole pairs. Thus it is expected that sunlight or UV light (wavelength range < 380 nm) should be the most effective followed by fluorescent light (wavelength < 400 nm) and other artificial light (wavelength range > 400 nm). The results obtained were in accordance with this order. The decolorized efficiency of single BB3 and RO16 with solar light irradiation was more efficient than that with artificial UV light irradiation. This phenomenon was partially attributed to a higher temperature of dye solution found under solar light irradiation. Previous work [9] also reported that the color removal rate of methylene blue with solar light irradiation was almost twice that of artificial UV light irradiation.

where Co/C is the normalized BB3 and RO16 concentration and k the apparent rate constant (1/min).

Effect of different light source

0.00

40.00

80.00

120.00

160.00

0 60 120 180 240 300 360 420 480 540Time (min)

% P

hoto

degr

adat

ion

BB3- 50 mg/l BB3- 75 mg/l BB3- 100mg/l

RO16- 50 mg/l RO16- 75 mg/l RO16- 100 mg/l

Figure 3: Effect of initial concentration and contact time on BB3 and RO16 for the photodegradation of single BB3 and RO16

-6.00

-4.00

0 60 120 180 240 300 360 420 480 540-6.00

-4.00

0 60 120 180 240 300 360 420 480 540

-2.00

0.00

2.00

4.00ln

C/C

o

Time (min)Time (min)

BB3- 50BB3- 50 mg/l

-2.00

0.00

2.00

4.00ln

C/C

o

BB3- 75 mg/l BB3- 100 mg/l

RO16- 50 mg/l RO16- 75 mg/l RO16- 100mg/l

Figure 4: Graph ln C/Co versus Time (min) for the effect of initial concentration and contact time for the photodegradation of single BB3 and RO16

0.00

2.00UV light (BB 3) UV light (RO 16)Sunlight (BB 3) Sunlight (RO 16)White fluorescent (BB 3) White fluorescent (RO 16)Halogen lamp (BB 3) Halogen lamp (RO 16)

1.60

0.40

0.80

C/

1.20

C o

0 60 120 180 240 300 360 420 480 540

Time (min)

Figure 5: Effect of different light sources for the photodegradation of BB3 and RO16 in single dye solutions

In the binary dye solution, however, the experimental results of photodegradation showed that the removal of both BB3 and RO16 was more effective using UV light than solar light. This may be due to the fluctuation in sunlight intensity. Nevertheless, sunlight can serve as an effective alternative and cheaper light source for the photodegradation of color pollutant.

4. COMPARISON OF SORPTION AND PHOTODEGRADATION inetic modeling has shown that, in the sorption study, the sorption capacities estimated from pseudo

first-order model are generally lower than those obtained experimentally, whereas the pseudo second-

2 uspension have been reported to be efficient due to the large surface area of the catalyst available for

reaction and the efficien s trans i [26], there are, however, problems associated wi iO n suspended m cult to separate the particle at the end of the process. Secondly, for photodegradation it is essential to ascertain sufficient supply of oxygen and efficient light source. Both of these would add to the capital and operating costs of the treatment process. In the present study,the formation of residues was also observed in the binary solution at the

e residue is currently order investigation.

K

order kinetic model which is based on the assumption that the rate-limiting step may be chemisorption yields good agreement between estimated and experimental sorption capacities. Similar phenomena have been reported in the biosorption of dyes on biosorbent [17, 19, 24, 25]. On the other hand, the kinetics of photodegradation using TiO2 catalyst fits the pseudo first-order model well.

The plots of Ct/Co versus Time (min) for single BB3 in both sorption and photodegradation are shown in Figure 6 for comparison. For the range of dye concentrations studied, photodegradation using TiO2 suspension is a more efficient method than sorption in the removal of BB3 in aqueous solution. Similar trend was observed in the removal of RO16 and in binary solution. Though TiOs

t mas2 i

fer w thin such system. First, it is diffith using T for

end of the experiments. The nature of th

0.00

0.40

0.80

1.20

1.60Sorption- 50 mg/l Photodegradation- 50 mg/l

Sorption- 75 mg/l Photodegradation- 75 mg/l

Sorption- 100 mg/l Photodegradation- 100mg/l

0 60 120 180 240 300 360 420 480 540

Ct/C

o

Time (min)

Figure 6: Graph Ct/Co versus Time (min) for the effect of initial concentration and contact time for the sorption and photodegradation of single BB3 5. CONCLUSION The present study has shown the effectiveness of MRH and TiO2 in the removal of BB3 and RO16 from synthetic solutions. Sorption was pH dependent and in the pH range of 4 to 7 appreciable amount of both dyes could be sorbed by MRH, both in single and binary dye solutions. The equilibrium data conform to Langmuir isotherms. A study of the kinetic models on sorption showed that sorption fitted the pseudo second-order model whereas photodegradation was explained by the pseudo first-order kinetics model. Both dyes can be separately degraded in an aqueous TiO2

ispersion under irradiation by ultraviolet lamp. However, due to the micrometric size of TiO2 articles, the use of aqueous suspension is not suited for practical applications.

dp

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“Intrinsic

KAJIAN KECEKAPAN ANOD KORBANAN ALOI AL-5.5ZN-2.0MG-XSN DI DALAM AIR LAUT TROPIKA

Abdul Razak Daud1, Mahdi Che Isa1, Muhamad Daud2,

Mohd Yazid Ahmad3, Nik Hasanudin Nik Yusof3

1Pusat Pengajian Fizik Gunaan, Fakulti Sains & Teknologi,

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor 2Institut Penyelidikan Teknologi Nuklear Malaysia (MINT), 43000 Kajang, Selangor

3Institut Penyelidikan Sains & Teknologi Pertahanan (STRIDE), 43000 Kajang, Selangor email: [email protected]; [email protected]

Abstrak. S al unsur aloian ai

d korbanan untuk ka marin. Aloi berkenaan dihasilkan dengan kaedah angan. Penciriannya dilakukan menggunakan kaedah pengutuban elektrokimia dan kapasiti arus. Keputusan

kajian menunj n penambahan r Sn ke dalam l-5.5Zn-2.0Mg telah m kapan anodnya. Kep n juga menu n kehadiran 1 n telah mengaktifka 2.0Mg dengan berkesan menyebabkan kadar kakisan meningk ng menghasilkan kecekapa inggi iaitu masing-ma g -1 dan 89.05%. Abstract. A st o aluminium ith nominal composition elements, 5.5 wt.% Zn,, 2 wt here x = 0.1, 0.5, 1.0, 1.5 and 2.0 for use anode in corrosion contr m alloys we ed by casting method. They were characterized using electroche ca nt c he results obtained showSn in the Al-5.5 -2 ode . It also showed that the .34 wt.% Sn has effectiv ac Mg alloy creased corrosion rate and anode efficiency to

x10 -1 and 89.05% respectively.

ata kunci: Aloi aluminium; kadar kakisan; kecekapan anod

engenalan

[1, 2].

m adalah logam yang reaktif, oleh itu mudah membentuk lapisan oksida apabila rdedah kepada oksigen. Kehadiran lapisan oksida menyebabkan logam aluminium menjadi pasif dan

, bagi memastikan aloi ini terus aktif di dalam persekitaran perasinya, bahan pengaktif turut diperlukan. Walaupun unsur seperti Hg atau In dapat meningkatkan eaktifan aloi aluminium tetapi penggunaan Hg khasnya bertentangan dengan sensitiviti perlindungan

ar sementara In pula sukar didapati dan mahal, maka unsur pengaktif alternatif adalah iperlukan [3]. Sehubungan dengan itu, Sn menjadi pilihan sebagai bahan pengaktif aluminium

muda . Tujuan kajian ini adalah untuk memfabrikasi aloi aluminium yang ditambah dengan Sn dan mengkaji kemampuannya sebagai anod korbanan bagi perlidungan keluli.

uatu kajian te, Zn 5.5%bt.

lah dijalankan bagi menentukan kecekapan aloi aluminium dengan komposisi nomin, Mg 2.0%bt, x%bt. Sn dengan x = 0.1, 0.5, 1.0, 1.5 dan 2.0 bagi kegunaan sebagwalan kakisan dalam persekitaranano

tuukkautusa

unsunjukka

aloi A eningkatkan kecen aloi Al-5.5Zn-

n anod yang t.34 %bt. Sat disampi

sin 9.80 x102 µm.tahun

udy n the anode efficiency of alloys w of alloying as sacrificial .0 .% Mg and x wt.% Sn w

ol in arine environment. The re preparmiZn

l polarization method and curre.0Mg alloy has increased its an

apacity. Tefficiency

ed that the addition of presence of 1

ely tivated the Al-5.5Zn-2.0 which in9.80 2 µm.year K P Keunikan aluminium seperti ringan dan tahan kakisan telah menjadikannya sangat berguna dalam pelbagai industri seperti industri pembinaan, pengangkutan, pembungkusan makanan dan sebagainya. Penggunaannya sebagai bahan bagi mengawal serangan kakisan bagi struktur-struktur keluli telah mendapat perhatian ramai penyelidik[1-3]. Walaupun aloi aluminium secara relatifnya agak baru sebagai bahan anod korbanan, namun ia mempunyai merit yang cukup baik kerana mempunyai beberapa kelebihan seperti ringan, mudah direkabentuk, nilai teori bagi kapasiti arus yang tinggi (2800 Aj/Kg) dan mudah diperolehi

Aluminiutekurang berkesan sebagai bahan anod korbanan. Jesteru itu, campuran dengan logam pengubahsuai seperti zink dan magnesium amat perlu bagi mengubah sifat elektrokimianya. Kajian terdahulu melaporkan campuran Zn dan Mg ke dalam aloi aluminium berjaya mengubah keupayaan kakisannya kearah lebih elektronegatif. Namun begituokalam sekitdberdasarkan ciri-ciri seperti tidak membentuk sebatian antaralogam dengan matriks aluminium,

h di dapati dan harganya lebih murah daripada indium

Kaedah

Seban n konve bahan aloi iaitu

mi eburan dipan minal aloi yang dibina ialah Zn dan Mg masing-masing sebanyak 5.5%bt. dan 2.0 %bt. sementara Sn sebanyak 0.1 %bt. hingga 2.0 %bt. dan selebihnya Al. Spesimen daripada aloi yang telah difabrikasi dianalisis komposisinya menggunakan spektrometer serapan atom mengikut piawai ASTM E 34-85[4]. Selepas

p

iAi Beratara = i 1

ni

g/mol (1)

Penyediaan Sampel yak enam aloi aluminium berbeza komposisi telah difabrikasi melalui teknik peleburansional di dalam persekitaran gas argon. Sn ditambah kedalam campuran

alu nium dan unsur-unsur lain seperti Zn dan Mg apabila suhu pemanasan mencapai 600oC. Laskan sehingga suhu 850 oC sebelum dituang kedalam acuan keluli. Komposisi no

kom osisi sebenar aloi diperolehi, beratara aloi di kira menggunakan persamaan 1 berikut[5],

fm

∑=

Kada an elektrokimia dengan kadar imbasan keupayaan 0.5 mV/saat pada julat keupayaan ± 250 mV disekitar keupayaan kakisan (Ekakis)[6]. Kadar kakisan dikira berdasarkan persamaan 2. Bagi kajian ini

n

berkenaan.

0.13 B Ikakis Kadar Kakisan

=

d

mil per tahun (2)

dengan fi = Pecahan mol jisim bagi unsur ke-i Ai = Berat jisim molekul relatif unsur ke-i

ni = Valensi bagi unsur ke-i Penentuan Kadar Kakisan

r kakisan ditentukan daripada plot Tafel yang diperolehi melalui kaedah pengutub

potentiostat model PC4/750 buatan Gamry yang dikawal oleh perisian Gamry Framework V4.2 telahdigu akan. Data diproses oleh perisian EChem Analyst V1.2 yang dipasang pada sistem peralatan

dengan B = beratara sampel (g.mol-1) d = ketumpatan sampel (g.cm-3) 1 mil per tahun = 25.4 mikrometer per tahun. Penentuan Kecekapan Anod dan Kapasiti Arus Kecekapan anod menunjukkan keberkesanan sesuatu anod melindungi logam lain daripada serangan kakisan. Ia dikira menggunakan data kapasiti arus sebenar dan kapasiti arus teori melalui persamaan 3. Kapasiti arus ditentukan dengan mengukur pemindahan cas (Amper.jam) per kehilangan jisim sampel. Bagi kajian ini keberkesanan aloi aluminium sebagai anod korbanan di dalam persekitaran marin ditentukan. Nilai kapasiti arus sebenar iaitu nilai uji kaji dan kapasiti arus teori ditentukan masing-masing melalui persamaan 4 dan 5 [7]. Sampel aloi dijadikan anod dan kepingan keluli dijadikan katod. Medium ujian ialah air laut tropika yang diambil disekitar pantai Lumut, Perak. Sampel aloi adalah berbentuk cakera berdiameter 1.80 cm dan berketebalan 0.30 cm manakala keluli (katod) pula dipotong berbentuk segi empat dengan dimensi 0.8 cm x 4.1 cm x 16.0 cm dengan nisbah luas permukaan dedahan bagi anod dan katod adalah 1:15 seperti yang dilakukan oleh penyelidik lain[8]. Sebelum ujian dimulakan semua sampel anod korbanan dan kepingan keluli dicanai menggunakan kertas SiC sehingga grit 1200, dibasuh dengan air suling dan dibilas dengan aseton.

Kapasiti arus sebenar Kecekapan anod = Kapasiti arus teori x100 % (3)

(M1 – M2) (4)Q Kapasiti arus sebenar = x1000 (Aj/kg)

dengan Q = Jumlah cas yang dipindahkan (Aj)

M = berat aloi sebelum ujian (kg) M

(96480 kulom /3600 saat Kapasiti arus teori = Beratara Al aloi, Kg (Aj/kg) (5)

1

2 = berat aloi selepas ujian (kg)

Berat awal setiap sampel anod korbanan direkodkan. Anod dan katod dipasang pada tangki

ujian dengan jarak antara permukaan masing-masing adalah 10 cm. Ketumpatan arus yang dibekalkan kepada sistem ialah 0.5 A/cm2 selama 72 jam. Jumlah pemindahan cas (Aj) direkodkan menggunakan kulometer. Selepas ujian, sampel anod dan keluli dibasuh dengan air dan dibersihkan dengan berus kemudian dikeringkan dalam aliran udara kering. Seterusnya sampel direndamkan pula ke dalam asid kromik (50 g/liter) selama lebih kurang 30 saat [9]. Sampel kemudian dibasuh dengan air suling dan dibilas dengan aseton dan seterusnya dikeringkan dalam aliran udara kering. Sampel seterusnya ditimbang bagi menentukan kehilangan jisim. Keputusan dan Perbincangan Komposisi sebanar aloi yang difabrikasi setelah dianalisis dengan spektrometer serapan atom adalah

inium berkenaan telah dikira dan disenaraikan pada Jadual 2. Secara umumnya menunjukkan yang kehadiran Sn meningkatkan kecekapan anod bagi aloi Al-5.5Zn-2Mg sebelum kecekapannya kembali menurun apabila aloi berkenaan mengandungi Sn sebanyak 1.95 %bt. Aloi Al-5.5Zn-2Mg-1.5Sn yang mengandungi 1.34 %bt. Sn menunjukkan kecekapan anod yang paling tinggi iaitu sekitar 89.05 %

seperti pada Jadual 1. Secara umumnya, komposisi sebenar aloi aluminium yang difabrikasi didapati menghampiri nilai komposisi nominal yang digunakan. Nilai beratara aloi yang dikira berasaskan komposisi sebenar aloi menggunakan persamaan 1 disenaraikan dalam Jadual 2.

Di samping itu, kehadiran unsur Fe dan Cu juga turut dikesan yang mungkin berpunca daripada bendasing yang terdapat di dalam logam-logam utama yang digunakan. Beberapa kajian terdahulu turut melaporkan kehadiran bendasing boleh membawa kesan buruk kepada sesetengah aloi bagi kegunaan dalam perlindungan kotod dimana ia turut mempengaruhi kecekapan atau prestasi anod korbanan[10,11]. Namun begitu, beberapa unsur pengubahsuai seperti Zn dan Mg manakala unsur pengaktif seperti Sn ditambah kepada aloi aluminium bertujuan meningkatkan prestasi aloi tersebut.

Jadual 1: Komposisi sebenar aloi aluminium yang dianalisis menggunakan spektrometer serapan atom.

Komposisi (% bt.) Sampel (Komposisi nominal) Zn Mg Sn Cu Fe Al

Al-5.5Zn-2Mg 5.51 1.82 TD 0.005 0.006 Baki Al-5.5Zn-2Mg-0.1Sn 5.49 1.85 0.07 0.004 0.008 Baki Al-5.5Zn-2Mg-0.5Sn 5.51 1.91 0.43 0.005 0.009 Baki

TD : Tidak dapat dikesan Nilai kapasiti arus sebenar, kapasiti arus teori dan kecekapan anod bagi aloi alum

Al-5.5Zn-2Mg-1.0Sn 5.52 1.89 0.96 0.002 0.008 Baki Al-5.5Zn-2Mg-1.5Sn 5.47 1.95 1.34 0.001 0.012 Baki Al-5.5Zn-2Mg-2.0Sn 5.52 1.79 1.95 0.019 0.032 Baki

berbanding dengan aloi aluminium yang lain yang dikaji dalam kajian ini. Bagi aloi Al-5.5Zntanpa kehadiran Sn hanya menunjukkan kecekapan 74.98% sahaja. Di samping itu, beberapa faktor lain seperti mikrostruktur, kewujudan fa

-2.0Mg

sa sekunder dan pengaruh bendasing juga boleh menyumbang kepada penurunan kecekapan [10,11]. Selain itu, prestasi aloi juga turut dikaitkan dengan kaedah

brikasi dimana kecacatan yang ketara kepada aloi turut mempengaruhi kapasiti arus dan kecekapan nod tersebut [12]. Namun begitu aloi yang difabrikasi bagi kajian ini tidak mempunyai kecacatan

fizikal yang ketara seperti retak atau liang.

Jadual 2: Beratara aloi dan kecekapan anod bagi aloi berkenaan sebagai anod korbanan di dalam air laut tropika pada suhu 27°C dan pH 8.1

Sampel (Komposisi nominal)

Beratara (g/mol)

Kapasiti arus sebenar (Aj/kg)

Kapasiti arus teori (Aj/kg)

Kecekapan (%)

faa

Al-5.5Zn-2Mg 2812.91 74.98 9.5379 2109.12 Al -5.5Zn-2Mg-0.1Sn 9.5368 2279.46 2809.30 81.14Al-5.5Zn-2Mg-0.5Sn 9.5826 2335.14 2794.90 83.55 Al-5.5Zn-2Mg-1.0Sn 9.6492 2470.96 2776.98 88.98 Al-5.5Zn-2Mg-1.5Sn 9.6906 2457.03 2759.15 89.05 Al-5.5Zn-2Mg-2.0Sn 9.7743 2263.03 2741.41 82.55

Rajah 1 dan Jadual 3 menunjukkan kehadiran unsur Sn menyebabkan keupayaan kakisan aloi Al-5.5Zn-2Mg berubah ke arah lebih negatif, ini bermakna aloi yang mengandungi Sn bersifat lebih anod berbanding dengan aloi tanpa Sn. Kehadiran Sn juga menunjukkan berlaku peningkatan kadar kakisan

punyai

engandungi 1.34 %bt. Sn di dapati mempunyai kecekapan sehingga 89.05%.

Rajah 1 Plot Tafel bagi menentukan kadar kakisan aloi Al-5.5Zn-2.0Mg-xSn di dalam medium air laut tropika pada suhu 27 °C, pH 8.1. (x%bt. Sn adalah komposisi nominal)

yang ketara berbanding dengan aloi Al-5.5Zn-2.0Mg tanpa Sn (Jadual 3). Kadar kakisan aloi-aloi ini jelas menyokong keputusan yang diperolehi bagi kecekapan anod dimana aloi yang memkecekapan yang rendah memberikan nilai kapasiti arus sebenar yang rendah. Keputusan ini mengesahkan yang Sn memain peranan sebagai pengaktif aloi Al-5.5Zn-2.0Mg yang mana aloi yangm

Dipercayai kehadiran Sn dalam aloi Al-5.5Zn-2.0Mg telah menyebabkan lapisan oksida

pelindu an

ngaktif t.

.95 %bt. (Jadual 2 dan 3). Ini kerana berlaku penomena tindak alas katod setempat memandangkan Sn lebih bersifat katod berbanding matriks aluminium. Ini akan

hagian daripada elektron digunakan untuk elindungi katod setempat tanpa dialirkan kepada logam struktur atau katod yang hendak dilindungi.

ng yang wujud pada permukaan aloi mengalami kecacatan dan tidak homogen. Kecacatlapisan oksida pelindung akan menurunkan rintangan permukaan aloi apabila dikutubkan danmenyebabkan aloi menjadi aktif dan kadar kakisannya meningkat. Peranan Sn sebagai unsur pealoi aluminium menjadi lebih ketara pada kepekatan yang bersesuaian di dalam aloi tersebuSekiranya kandungan Sn berlebihan, kadar kakisan dan kecekapan anod akan kembali menurun.Dalam kajian ini penurunan kecekapan anod dan kadar kakisan berlaku apabila kandungan Sn dalamaloi berkenaan ditingkatkan kepada 1bmenyebabkan kecekapan arus berkurang kerana sebam

Jadual 3: Keupayaan dan kadar kakisan bagi aloi Al di dalam air laut yang diperolehi daripada plot Tafel.

Bil Aloi Ekakis

V(EKT) Ikakis

(µA.cm-2) Kadar Kakisan (µm.tahun-1)

1 Al-5.5 Zn-2Mg -1.370 8.660 1.00 x 10 2

2 Al-5.5Zn-2M3 Al-5

g-0.1Sn -1.420 36.90 4.22 x 102 .5Zn-2Mg-0.5Sn -1.430 33.50 3.84 x 102

2

4 Al-5.5Zn-2Mg-1.0Sn -1.540 21.90 2.51 x 102 5 Al-5.5Zn-2Mg-1.5Sn -1.580 81.80 9.80 x 102 6 Al-5.5Zn-2Mg-2.0Sn -1.650 61.50 7.05 x 10

EKT = elektrod kalomel tepu

menunjukkan kandungan Sn dalam aloi Al-5.5 Zn-2Mg memberi kesan dap sifat elektrokimia aloi aluminium. Aloi Al-5.5Zn-2Mg yang mengandungi 1.34

bt. Sn memberikan kecekapan tertinggi berbanding komposisi lain bagi aloi aluminium yang dikaji. erdasarkan kepada nilai kecekapan aloi, ternyata kehadiran unsur Sn yang bertindak sebagai engaktif berjaya menambahkan kapasiti arus dan juga meningkatkan kadar kakisan aloi. Aloi luminium dengan komposisi kimia unsur-unsur utama 5.47 %bt. Zn, 1.95 %bt. Mg dan 1.34 %bt. Sn

banan paling cekap berbanding dengan aloi yang dikaji iaitu mempunyai ecekapan anod sebanyak 89.05%.

enghargaan:

sia di atas sokongan kewangan melalui y rgaan juga kepada Institut Penyelidikan

Sains dan Teknolo peralatan pe Rujukan 1. Lin, J. C. and Shih, H. C. (1987). “Improvement of the current efficiency of an Al-Zn-In anode

by heat treatment”. J. Electrochem. Soc. 134(4). 817-823.

Kesimpulan Kajian yang telah dijalankan yang ketara terha%Bpamerupakan anod kork P Para penulis merakamkan penghargaan kepada Kerajaan Malaygeran pen elidikan, IRPA 09-02-02-0118-EA295. Pengha

gi Pertahanan (STRIDE), Kementerian Pertahanan Malaysia di atas kemudahannyelidikan yang dibekalkan.

2. Bessone, J. B., Baldo, R. A. S. and Micheli, S. M. (1981).“Seawater testing of Al-Zn, Al-Zn-Sn and Al-Zn-In sacrificial anode”. Corrosion 37(9). 533-539.

3. Mathiyarasu, J., Nehru, L. C., Subramaniam, P., Palaniswamy, N. and Rengaswamy, N. S. (2001). “Synergistic interaction of indium and gallium in the activation of aluminium alloy in aqueous chloride solution”. Anti-Corr Methods & Materials 48(5). 324-329.

4. ASTM E 34-85 (1985). “Standards test methods for chemical analysis of aluminum and aluminum alloys”. American Society for Testing and Materials, Philadelphia, USA.

5. ASTM G 102-89 (1989). “Standards practice for calculation of corrosion rates and related information from electrochemical measurements”. American Society for Testing and Materials, Philadelphia, USA.

6. Siebert, O. W. (1985). “Laboratory electrochemical test methods”. Dlm. Laboratory Corrosion Tests and Standards (Haynes, G. S. & Baboian, R., eds.), ms 65-90. Philadelphia : American Society for Testing and Materials.

7. ASTM G 97-97 (1997). “Standards test methods for laboratory evaluation of magnesium sacrificial anode test specimen for underground applications”. American Society for Testing and Materials, Philadelphia, USA.

t

ns in anode manufacturing”. Corrosion paper 00679, N

um”. Corrosion 49(11). 895-902. 12. Sherwood, L. (1994). “Sacrificial Anodes”. Dlm Corrosion Control Volume 2, 3rd edn. (Shreir,

L. L., Jarman, R.A. & Burstein, G. T., eds.), ms 10:29-10:54. London: Butterworth-Heinemann.

8. Wang, W., Hartt, W. H. and Chen, S. (1996). “Sacrificial anode cathodic polarization of s eel inseawater: Part 1-A novel experimental and analysis methodology”. Corrosion 52(6). 419-426.

. Lenar, J. (2000). “Laboratory evalutio9ACE, Houston, Texas USA.

10. Salinas, D.R., Garcia, S.G and Bessone, J.B. (1999). “Infuence of alloying elements and microstructure on aluminium sacrifcial anode performance: case of Al-Zn”. Journal. of Appl. Electrochem. 29. 1063-1071.

11. Breslin, C. B., Friery, L. P., and Carrol, W. M., (1993). “Influence of impurity elements on electrochemical of aluminium activated by indi

SQUARE WAVE CATHODIC STRIPPING VOLTAMMETRIC TECHNIQUE FOR DETERMINATION OF AFLATOXIN B1 IN GROUND NUT SAMPLE

Mohamad Hadzri Yaacob1, Abdull Rahim Hj. Mohd. Yusoff2 and Rahmalan Ahamad2

1School of Health Sciences, USM, 16150 Kubang Krian, Kelantan, Malaysia 2Chemistry Dept., Faculty of Sciences, UTM, 81310 Skudai, Johor, Malaysia

Abstract An electroanalytical method has been developed for the detection and determination of the 2,3,6a,9a-tetrahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin B1, AFB1) by a square wave cathodic stripping voltammetric (SWSV) technique on a hanging mercury drop electrode (HMDE) in aqueous solution with Britton-Robinson Buffer (BRB) at pH 9.0 as the supporting electrolyte. Effect of instrumental parameters such as accumulation potential (Eacc), accumulation time (tacc), scan rate (v), square wave frequency, step potential and pulse amplitude were examined. The best condition were found to be Eacc of -0.8 V, tacc of 100 s, v of 3750

frequency of 125 Hz, voltage step of 30 mV and pulse amplitude of 50 mV. Calibration curve n the range of 0. 5 x 10-8 M. Relative standard for a centration of 0.01 uM was 0.83%

ith a peak potential of -1.30 V (against Ag/AgCl). The recovery values obtained in spiked ground ut elute sample were 94.00 +/- 0.67 % for 3.0 ppb, 91.22 +/- 1.56 % for 9 ppb and 92.56 +/- 2.00 %

0 ppb of AFB1. The method was applied for determination of the AFB1 in ground nut samples fter extraction and clean-up steps. The results were compared with that obtained by high erformance liquid chromatography (HPLC) technique.

bstrak Satu kaedah elektroanalisis telah dibangunkan untuk mengesan dan menentukan 2,3,6a,9a-trahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin 1, AFB1) menggunakan teknik voltammetri perlucutan katodik denyut pembeza di atas elektrod tisan raksa tergantung (HMDE) di dalam larutan akuas dengan larutan penimbal Britton-Robinson

n penyokong. Kesan parameter peralatan seperti eupayaan pengumpulan (Eacc), masa pengumpulan (tacc), kadar imbasan (v), frekuensi gelombang ersegi, kenaikan keupayaan dan amplitud denyut telah dikaji. Keadaan terbaik yang diperolehi dalah Eacc; -0.8 V, tacc; 100 s, v; 3750 mV/s, frekuensi; 125 Hz, kenaikan keupayaan; 30 mV dan mplitud denyut; 50 mV. Keluk kalibrasi adalah linear pada julat di antara 0.01 ke 0.15 uM dengan ad pengesan pada 0.125 x 10-8 M. Sisihan piawai relatif untuk 5 kali pengukuran AFB1 dengan

.83 %. Nilai perolehan semula di dalam larutan elusi sampel kacang yang adalah 94.00 +/- 0.67 %, 91.22 +/- 1.56 % dan h digunakan untuk menentukan kandungan AFB1

di dalam

Aflatoxins (AF), the mycotoxin produced mainly by Aspergillus flavus and parasiticus and

display strong carcinogenicity [1]. They are dangerous food and contaminants and represent a worldwide threat to public health. AFB1, B2, G1 and G2 and their metabolites M1 and M2 are the most common, and of these, AFB1 and AFG1 are observed most frequently in food [2]. Of these, researches have shown AFB1 (Fig 1) exhibits most toxic [3] with the order of toxicity is AFB1 > AFG1 > AFB of

mV/s, is linear i 01 to 0.15 uM with a detection limit of 0.12deviation replicate measurements of AFB1 (n = 5) with a conwnfor 15.ap AteBti(BRB) pada pH 9.0 bertindak sebagai larutakbaahkepekatan 0.01uM ialah 0disuntik dengan 3.0 ppb, 9 ppb dan 15.0 ppb AFB192.56 +/- 2.00 % masing-masingnya. Kaedah ini tela

sampel kacang tanah selepas proses pengekstraksian dan pembersihan dijalankan. Keputusan yang diperolehi telah dibanding dengan keputusan dari kaedah kromatografi cecair berprestasi tinggi. Keywords: square wave stripping voltammetry, HMDE, aflatoxin B1, ground nut Introduction

2 > AFG2 indicates that the terminal furan moiety AFB1 is a critical point for

1 Corresponding address: Chemistry Dept, Faculty of Science, UTM, 81310 Skudai, Johor, Malaysia tel: 07-553 4492

O

O

O

OO

O

determining the degree of biological activity of this group of mycotoxins [4]. Many countries including Malaysia have stringent regulatory demands on the level of aflatoxins permitted in imported and traded commodities.

ne of the foodstuffs which is most occurrence of AFB1 is ground nut. In Malaysia, the

AFB1 level in peanut is regulated with maximum level that cannot be greater than 15 ppb [5]. Several analytical techniques for quantitative determination of the AFB1 in ground nut have been proposed such as thin layer chromatograhpy [6], high performance liquid chromatography[ 7,8,9 ]and an enzyme-linked immunosorbent assay, ELISA [10], All these methods, however, require specialist equipm skilled personel and expensive instruments and high maintenance cost [11].

ue to all these reasons, a voltammetric technique which is fast, accurate and require low cost equipment [12,13] is proposed. A square wave cathodic stripping which is presented in this paper is one of the voltammetric technique that in particularly, has a few advantages compared to other voltammetric technique such as high speed, increased analytical sensitivity and relative insensitivity

the presence of dissolved oxygen [14]. Previous experiment using cyclic voltammetric technique howed that AFB1 reduced at mercury electrode and the reaction is totally irreversible [15]. This ork aimed to study and develop a SWSV method for determination of AFB1 at trace levels and to

s been published regarding this xperiment until now.

Experiment

Apparatus

Square-wave voltammograms were obtained with Metrohm 693 VA Processor coupled with a Metrohm 694 VA stand. Three electrode system consisted of a hanging mercury drop electrode (HMDE) was used as the working electrode, Ag/AgCl/3 M KCl reference electrode and a platinum wire auxiliary electrode. A 20 ml capacity measuring cell was used for placing supporting electrolyte and sam le analytes. All measurements were carried out at room temperature. All pH measurements were made with Cyberscan pH meter, calibrated with standard buffers at room temperature. Reagents

FB1 standard (1mg per bottle) was purchased from Sigma Co. and was used without further purifica d

)

Figure 1 Chemical structure of AFB1

O

ent operated by D

toswdetermine this aflatoxin in ground nut samples. No such report hae

p

Ation. Stock solution (10 ppm or 3.21 x 10-5 M) in benzene:acetonitrile (98:2) were prepare

and stored in the dark at 14 0 C. The diluted solution were prepared daily by using certain volume of stock solution, degassed by nitrogen until dryness and redissolved in Britton-Robinson buffer (BRBsolution at pH 9.0. Britton-Robinson buffer solutions (prepared from a stock solution 0.04 M phosphoric (Merck), boric (Merck) and acetic (Merck) acids; and by adding sodium hydroxide (Merck) 1.0 M up to pH of 9.0. All solutions were prepared in double distilled dionised water (~ 18M Ω cm). All chemicals were of analytical grade reagents.

Procedure

For voltammetric experiments, 10 ml of Britton-Robinson buffer solution with pH 9.0 was laced in a voltammetric cell, through which a nitrogen stream was passed for 600 s before recording e voltammogram. The selected Eacc = - 800 mV was applied during the tacc = 100 s while the

olution was kept under stirring. After the accumulation time had elapsed, stirring was stopped and e selected accumulation potential was kept on mercury drop for a rest time (tr = 10 s), after which a

potential scan was performed between -1.00 as initial potential (Ei) and finished at -1.400 V as final otential (Ef ) by SWSV technique.

rocedure for the determination in ground nut samples

AFB1 was extracted according to the standard procedure developed by Chemistry epartment, Penang Branch, Ministry Of Science, Technology and Innovation, Malaysia [16]. 1ml f the final solution from extraction and clean-up steps in chloroform was pipette into amber bottle,

degassed with nitrogen and redissolved in 1ml of BRB solution. 200 ul of this solution was spiked to 10 ml supporting electrolyte in volumetric cell. After that, the general procedure was applied and

lowed by a standard addition of 10 pb of AFB1 standard addition and voltammogram of sample with AFB1 standard was recorded.

esult and discussion Using previous differential pulse stripping voltammetry (DPCSV) optimum parameters [17],

WSV was run to determine 0.1 uM AFB1 in BRB pH 9.0. It gave a single reduction signal with eak height (Ip) of 250 nA at peak potential (Ep) of -1.26 V (against Ag/AgCl). The SWS oltammograms shows improved Ip compared to that obtained bt DPCSV where the Ip was increased lmost 4 times as shown in Figure 2.

Cyclic voltammogram of AFB1 in BRB pH 9.0 is shown in Figure 3 which only produced a

athodic peak that indicates the non-reversibility of the electrode process [18].

Figure 2 Voltammograms of 0.1 uM AFB1 obtained by (a) DPCSV and (b) SWSV techniques. Experimental condition; for DPCSV: Ei = -1.0 V, Ef = -1.4 V, Eacc

= -0.6 V, tacc = 80 s, υ = 50 mV/s and pulse amplitude = 80 mV and for SWSV: Ei = -1.0 V, E = -1.4 V, E = -0.6 V, t = 80 s, frequency = 50 Hz, voltage step = 0.02,

pthsth

p P

Do

involtammogram of sample was recorded. This experiment was folp

R

Spva

c

f acc accamplitude = 50 mV and υ = 1000 mV/s.

Figure 3 Cyclic voltammogram of AFB1 in BRB pH 9.0. Experimental conditions:1.5 V, Ehigh = 0 and scan rate = 200 mV/s.

050

100150200250300

5 6 7 8 9 10 11 12 13 14

pH of BRB

I p (n

A)

Ei = 0, Elow = -

e s

10 uM AFB1 using SWSV technique. The strumental parameters are the same as in Figure 2.0.

The effect of the pH of the BRB on the stripping was studied in a pH range of 6 – 13 (Figur

4). The Ip increased slowly with increasing pH up to 8.0 followed with sharply increased for pH 8.0to 9.0, then decreased in pH 10.0 and continuously decreased in a range of 10 – 13. Thus pH 9.0 wachosen for the analysis. This result is not contradicted with that found by Smyth et al. (1979) when they performed polarographic study of AFB1 [19].

Figure 4 Influence of pH of BRB on the Ip of 0.in

Figure 5 shows a dependence of the Ep on pH. Shifting of the Ep towards the negative

direction at higher pH implies that the reduction process takes up hydrogen ions [20]. A double bond in aromatic ring conjugates with ketone group, in general, undergoes a reduction at mercury electrode.The suggested mechanism of this reaction in BRB pH 9.0 is illustrated in Figure 6 as reported by Smyth et al. (1979) [21].

1.181.2

1.221.241.261.281.3

1.321.34

5 6 7 8 9 10 11

pH

EV)

p (-

O

OO

C H 3

O

OO

C H 3

2H +

2 H 2O

D im er + 2 O H -

2e -

2 2

igure 5 Relationship between Ep of AFB1 with pH of BRB

igure 6 Mechanism for reduction of AFB1 at mercury electrode in BRB pH 9.0 Optimisation ng analysis

The voltammetric determination of ana levels normally invol all current response. For that reason it is importan all those parameters w ave an influence on the mea ured current. The effect of Ei Eacc , tacc, frequency, voltage step and amplitude were studied. Square-wave voltammetric technique used with stirring. For this stud , 1.0 x 10-7 M of AFB1 was spiked into supporting electrolyte.

A study of t influence of Ei showing a peak height (Ip) was obtained for Ei = -1.0 V (Figure

7). The Ip was slow i more negative than -1.0 V. This value was chosen for subsequent studies further optimisation step. Influence of Eacc to Ip of AFB1 was investigated where the Eacc was varied between 0 to -1.4 V. The maxi alue of Ip obtained at -0.8 V ) as shown in Figure 8. This value was selected for subsequent experiments.

The dependence of Ip on tacc was studied. The effect of tacc on the Ip was studied where tacc was

varied from 0 to 160 s. The result is shown in Figur to 100s according to equation y = 3.8557x + 21.383 (n=6) 2 = 0.9936, then it increased rather slowly leveling off at about 140 s. At 160 s, Ip decreased which may be due to the electrode saturation [21]. Thus, 100 s was appeared to be an optimum tacc for e pre-concentration prior to stripping.

F

F

of condition for the strippi

lytes at tracet to optimise

ves very smhich may h

s , was y

hely decreased for E

mum v (366 nA

e 9 which reveals that there is linearly with R

up

th

050

100150200250300

0.2 0.4 0.6 0.8 1 1.2 1.4

Ei (-V)

I p (n

A)

050

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

100

Eacc (-V)

150200

0

I p (n

A) 25

300350400

050

0 40 80 120 160 200

100150200250300

I p (n

A)

350400450

Tacc (s)

Figure 7 Effect of Ei on the Ip of 0.1 uM AFB1 in BRB pH 9.0

Figure

amplituwere: 25 z for the frequency, 0.01 to 0.04 for the voltage step and 25 – 100 mV for pulse

]. At higher pincreases. Finally, the condition selected were: frequency = 125 Hz, voltage step = 0.03 V and pulse amplitude = 50 mV (Figures 10 to 12). Under optimised parameters, Ip of AFB1 was 956 nA which is

8 Effect of Eacc on the Ip of 0.1 uM AFB1 in BRB pH 9.0

Figure 9 Effect of tacc on the Ip of 0.1 uM AFB1 in BRB pH 9.0 For other instrumental condition such as square wave frequency, step potential and pulse de were examined, varying one of them and maintaining constant others. The variable ranges to 125 H

amplitude. Generally, the Ip increase by increasing all of these instrumental parameters [22otential values the peak width increase; at higher frequency values the current background

16 tim s higher compared to that obtained by DPCSV. Figure 13 shows voltammograms of 0.1 uM btained by SWSV and DPCSV techniques.

00 25 50 75 100 125 150

Frequency (Hz)

200

400I p

600

800 (n

A)

1000

0

200

400

600

800

1000

A)

1200

0 0.01 0.02 0.03 0.04 0.05

Voltage step (V)

I p (n

0

200

400

600

800

1000

1200

0 0.025 0.05 0.075 0.1 0.125

Amplitude (V)

I p (n

A)

eAFB1 o

Figure SV frequency

Figure 11 Dependence of the Ip of AFB1 on SWSV voltage step Figure 12 Dependence of the Ip of AFB1 on SWSV pulse amplitude

10 Dependence of the Ip of AFB1 on SW

Voltammograms of AFB1 obtained by (a) DPCSV and (b) SWSV techniques in BRB pH

y = 62.373x + 246.15R2 = 0.9956

0

200

400

600

800

1000

1200

1400

0 5 10 15 20

[AFB1] / 10-8 M

I p (n

A)

Figure 13 9.0.

Voltammetric determination of AFB1 and analytical characteristics of the method

Using the selected conditions already mentioned, a study was made of the relationship between Ip and concentration. There is a linear relationship in the concentration range 0.01 to 0.15 uM as shown in Figure 14. Limit of detection (LOD) was 0.389 ppb (0.125 x 10-8 M) which was determined by standard addition of low concentration of AFB1 until obtaining the sample response that is significantly difference from blank [23]. Relative standard deviation (RSD) of the analytical signals at several measurement (n=5) of 0.10 uM was 0.83%.

Figure 14 Calibration plot of AFB1 in BRB pH 9.0 obtained by SWSV technique. Determination of AFB1 in ground nut samples The proposed method was applied to the analysis of the AFB1 in ground nut samples. Recovery studies were performed by spiked with difference concentration levels of AFB1 standard into eluate of ground nut sample. In this case the concentrations used were 3 ppb (0.963 x 10-8 M), 9 ppb (2.889 x 10-8 M) and 15 ppb (4.815 x 10-8 M). The results of these studies are shown in Table 1. For analysis of AFB1 in ground nut samples, the standard addition method was used in order to eliminate the matrix effects. Figure 15 show voltammograms of real sample together with spiked AFB1 standard. Table 2 listed the content of AFB1 in 6 samples obtained by proposed technique compared with that obtained by HPLC. The results show that there are no significant different of AFB1 content obtained by both techniques.

Table 1 Percent recovery of AFB1 spiked in real samples (n=3)

Amount added (ppb)

Amount found (ppb) Recovery (%) n=3

3.00

9.00

2.82 +/- 0.02

94.00 +/- 0.67

15.00

8.21 +/- 0.14

13.88 +/- 0.30

91.22 +/- 1.56

92.53 +/- 2.00

Figure 15 SWS voltammograms of real sample (b) and spiked AFB1 (c) obtained in BRB pH 9.0 as the supporting electrolyte (a) Table 2 AFB1 content in ground nut samples by proposed technique compared with those obtained by HPLC.

AFB1 content in real sample

No of sample

By SWSV

By HPLC

1

3

4

5

6

ND

ND

9.21

13.92

36.00

ND

ND

8.25

14.34

36.00

2

ND

ND

e.

. Tanaka, T and Toyoda, M. (2001). “Determination of aflatoxinsB1, es using a multifunctional column clean-up” J. Of Chromatography A,

932. 153-157. 2.

M.K.L., Kniseley, R.N and Svec, H.J (1983) “Coupled-Column for quantitating low vels of aflatoxins” J . Assoc. Off. Anal. Chem. 66, 905-908.

.

rocedure followed up by high-performance liquid chromatographic analysis and post-column

immunoassay for the detection flatoxin B1” Anal Chim Acta, 444. 187-191.

12. Braitina, Kh. Z., Malakhova, N.A. and Stojko, Y. (2000) “Stripping voltammetry in environmental and food analysis” Fresenius J Anal Chem 368. 307-325

3.

Conclusion

A SWSV technique was successfully developed for the determination of AFB1 in ground nut as an alternative method for determination of AFB1 which is sensitive, accurate and fast technique. The results are not significant different with that obtained by accepted technique used for routine analysis of AFB1. Acknowledgement

One of the author would like to thank University Science Malaysia for approving his study

leave and financial support to carry out his further study at Chemistry Dept., UTM. We also indebt to UTM for short term grant (Vot No 75152/2004) and to Chemistry Department, Penang Branch, Ministry of Science, Technology and Innovation (MOSTI) for their help in analysis of aflatoxin in ground nut samples using HPLC techniqu

References

1. Akiyama, H. Goda, YB2, G1 and G2 in spic

Yoruglu, T, Oruc, H.H. and Tayar, M. (2005) “Aflatooxin M1 levels in cheese samples from some provinces of Turkey” Food Control. 16(10): 883-895.

3. World Health Organisation in: IARC Monograph on the evaluation of carcinogenic risk to human, WHO, Lyon, 1987.

4. Hall, A.J., Wild, C.P in: Eaton, D.L., Groopman, J.D. (Eds). “The toxicology of aflatoxins: Human Health, Veterrinary and Agricultural Significance” Academic, New York, 1994.

5. Malaysian Food Act (1983) Act No 281, Reviewed 2002, Food Quality Control Dept, Ministry of Health, Malaysia.

6. Bicking,le

7 Beebe, B.M. (1978). “Reverse phase high pressure liquid chromatographic determination of aflatoxins in foods” J. Assoc. Off. Anal. Chem. 81. 1347-1352.

8. Cepeda, A., Franco, C.M., Fente, C.A., Vazquez, B.I., Rodriguez, J.L., Prognon, P. and Mahuzier, G. (1996) “Postcolumn excitation of aflatoxins using cyclodextrins in liquid chromatography for food analysis” J Of Chrom A. 721. 69-74.

9. Garner, R.C., Whattam, M.M. , Taylor, P.J.L. and Stow, M.W ( 1993) “Analysis of United Kingdom purchased spices for aflatoxins using immunoaffinity column clean up p

derivatization with pyridium bromide perbromide” J. Chromatography, 648. 485-490 10. Beaver, R.W., James, M.A. and Lin ,T.Y. (1991). “ELISA-based screening test with liquid

chromatography for the determination of aflatoxin in corn” J. Assoc.Off. Anal. Chem , 74: 827 – 829

11. den, S.R. and Strachan, N.J.C.(2001). “Novel colorimetric Garof a

1 Skrzypek, S., Ciesielski, W., Sokolowski, A., Yilmaz, S. and Kazmierczak, D. (2005) “Square wave adsorption stripping voltammetric determination of famotidine in urine”Talanta. Article in press.

14. Economou, A., Bolis, S.D., Efstathiou, C.E. and Volikakis, G.J (2002) “A virtual electrochemical instrument for square wave voltammetry”.Anal. Chim. Act. 467. 179-188.

15. Yaacob, M.H., Mohd Yusoff, A.R. and Ahmad, R. (2003). “Cyclic voltammetry of AFB2 at the mercury electrode”. Paper

thpresented at Simposium Kimia Malaysia ke 13 (SKAM-13), 9

– 11 September 2003, Kucing, Sarawak, Malaysia. 16.

Paper nd th

try”. J of Electroanal. Chem.

Standard procedure for determination of aflatoxins (2000). Chemistry Dept. Penang Branch, Ministry of Science, Technology and Innovation (MOSTI), Malaysia – unpublished paper.

17. Yaacob, M.H., Mohd Yusoff, A.R. and Ahamad, R. (2005). “Determination of the aflatoxin B1 in ground nut by differential pulse cathodic stripping voltammetry technique”. presented at 2 National Seminar On Chemistry, 14 April 2005, Universiti Sumatera Utara, Medan, Indonesia.

18. Rodriguez, J., Berzas, J.J., Casteneda, G. and Rodriguez, N. (2005). “Voltammetric determination of Imatinib (Gleevec) and its main metabolite using square-wave and adsorptive stripping square-wave techniques in urine samples”. Talanta. 66. 202-209.

19. Smyth, M. R., Lawellin, D. W. and Osteryoung, J.G. (1979). “Polarographic study of Aflatoxin B1, B2, G1 and G2: Application of differential pulse polarography to the determination of Aflatoxin B1 in various foodstuffs” Analyst. 104. 73-78

20. Sun, N., Mo, W-M., Shen, Z-L. and Hu, B-X. (2005). “Adsorptive stripping voltammetric technique for the rapid determination of tobramycin on the hanging mercury electrode”. J Pharm. Biomed. Anal. Article in press.

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ASSESSMENT OF ELEMENTAL POLLUTION IN THE STRAIT OF MELAKA

NGI, 43000 Bangi, Malaysia

t Research Institute, King Abdul-Aziz City for Science and Technology (KACST), P.O. BOX 6086, RIYADH 11442, Saudi Arabia

Lu, , Sr, Ta, Th, Ti, U, V, Yb, and Zn were determined in grab sediment samples of the Strait of Melaka. The total concentration of the most elem ated for average shales and mean crustal materials except As, Ag, Cd, Sb, Cs, Hf, Rb, Br, Th, U, Yb and Pb. K0 Instrumentation Neutron Activation Analysis standardization technique is valuables in analyzing various samples types including sediment samples. Moreover, K0-INAA is simple, flexible, accurate, and precise. 1. Introduction

Nowadays environmental pollution represents a major concern worldwide [1, 2, 3, and 4].

Especially the marine environmental pollutions consider as a dangerous pollution because of the easiest way of its wide extend over long distance within a short period of time. The Strait of Melaka situated at west coast of peninsular Malaysia and surrounded by four countries, which are namely Malaysia, Singapore, Indonesia and Thailand. The length of Strait of Melaka is about 1111 Km, with the wider width of about 407 Km near the north-west entrance and the shortest width of about 15 Km at the south-east entrance near the Riau Archipilago [5]. Nationally, approximately 70% of the total land of fish in Malaysia produces from Strait of Melaka [6]. Today the Strait of Melaka is one of the most important and busiest waterways in the world. One quarter of global trade pass through the strait everyday. Moreover, approximately a half of the world’s oil passes through the strait everyday. This will lead to increasing the pollution in the strait, in particular the heavy metals. So, the sediments may serve as a mean to evaluate the extent of contamination in aquatic system. The heavy metals contamination may extent its hazards effect to aquatic life, system and human health, especially to human consumers of seafood’s through bioaccumulation in food chain. For example between 1975 and 1993 there were 75 shipping incidents in the Strait of Melaka reported by the Marine Department of Malaysia. Where 34 of 75 resulted in oil spills [7].

The main objectives of this research are: a) to determine the horizontal and vertical distributions of the heavy metals pollution in strait of Melaka, b) to establish base-line data for the heavy metals

Awad A. Alzahrany1, 3, Ab. Khalik. H. Wood2, Elias Saion1, Md Suhaimi Elias2, Zainal Abidin

Sulaiman1, Wee Boon Siong2

1University Puta Malaysia (UPM), College of Sciences, Department of physics, 43400 Serdang, Selangor, Malaysia

2Malaysia Institute for Nuclear Technology Research (MINT) BA

3A omic Energy

ABSTRACT

In this study, 35 marine sediment samples along Strait of Melaka, representing the west coast of peninsular of Malaysia were analyzed by using instrumental neutron activation analysis (INAA). This work is carried out to evaluate the level of elemental pollution in the water body. In addition, iinndduuccttiivveellyy ccoouupplleedd ppllaassmmaa--mmaassss ssppeeccttrroossccooppyy ((IICCPP--MMSS)) tteecchhnniiqquuee wwaass uusseedd ffoorr nnoonn--mmeeaassuurraabbllee eelleemmeennttss bbyy IINNAAAA.. The concentration of Ag, Al, As, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hf, K, La, Mg, Mn, Mo, Na, Ni, Pb, Rb, Sb, Sc, Sm

ents found lower than the concentrations estim

po r only the grab sediment samples that collected f of Melaka.

re h mite lem alo ait [8] study s ce elements concentrations of Strait of Melaka using ICP-MS and AAS, he presented the results as only log-log plots of metal contents vs. Al contents expect Cu, Zn and Cr he presented in range values a for Cu .0-119.6 p r Zn, and 10.7-69.1 ppm for Cr. 1. Experimental 1.1 mpling and sampling preparation

In this research, 35 grab marine sediment sa trait of aka from pling

location were collected. The 35 sampling location a it of M are shown ure 1. The coordinates of sampling locations were determ Positio System (GPS) as listed in Table 1. The sediment samples were collected between February-March 2004.

llution in strait of Melaka, and cc)) TToo ddeetteerrmmiinnee tthhee sseeddiimmeenntt ppoolllluuttiioonn ttrreennddss.. This paper will coverom strait

Thehas

ave been liome tra

d studies of e ental pollution ng the Str of Melaka. Din

s 3.3-18.0 ppm , 29 pm fo

Sa

mples along s Mel 12 samnd map of Strained by Global

elaka ning

in Fig

Figure 1. Map of Strait of Melaka showing the location of collection samples

The grab sediment samples were collected from the top of about 23 cm layer of bottom sediments using standard ponar grab sampler which has a 8.2 liter volume. The wet sediment samples were stored in polyethylene bottles and the samples refrigerated at -5 ºC immediately after the researchers return back to the laboratory, to prevent any change in heavy metals distribution among different phases [9]. Then, the sediment samples dried in an oven at 65 ºC for about 5-10 days until to constant dry weight was achieved. After that, the dried sediment samples were grinded manually and grinded by using electronic agate homogenizer up to obtain homogenous powders of about 2mm mesh size and stored in polyethylene bottles for analysis.

In neutron activation analysis (NAA), each dried sediment sample was shaked enough manually plicate weight ranging from 0.05 to 0.1 g for short irradiation and 0.15-0.20 g fand a du or long

radiation were taken into a polyethylene vial and heat-sealed. On the other hand, the multi-elements sta olu hort iati prepa ated on aper in the same polyeth nd h oreove eennssuurree aa pprreecciissiioonn enneerraatteedd ddaattaa aa pprrooppeerr qquuaality controll aanndd qu ssurraannccee hhaass bbeeeenn iinnccorporated in tthhee aannaallyyttiiccaall pprroocceedduurreess.. AAccccu yy aann ooff tthh chhnniiqquuee aallyyssiiss wwee bbyy ttwwoo mm ddss.. FFiirrsstt,, bbyy iirrrraadd nngg aanndd gg cceerrttiif ccee mmaattee ((CCRRMM)) ss l--77 aalloonngg ww aacchh ggrroouupp ooff ssaammppllee .. AAss ss TTaabbllee 22,, t aavveerraaggee rreess llttss ffoouunndd ffoo OOIILL--77 CCee dd RReeffeerreennccee MMaatt ll ((CCRR ttiiffiiee eennddeedd uueess tthhee rr hee eelleemmeenn tthhee rraannggee ooff 7700 %% o 111155 ccoonndd,, bb ngg AAlluumm mm wwiirree cc ff 00..11%% ggoo AAuu,, ddiiaammeetteerr 00..55mm lleennggtt mm,, IIRR nngg wwiitth cchh ggrroouupp oo ssaammpplleess aanndd aa ppllyy K0-INAA ssttaann iizzaattiioon uuee.. Also, aa sshhoowwnn iinn TTaabb ee 22,, tthhee aavvee llttss ffoouunndd ffoo AAEEAA--SSOOIILL--77 CCeerrttifiedd RReeffee aatteerriiaall ((CCRRM)) wwiitthh cceerrttiiffiiee aanndd rreeccoommmmee eedd vvaalluueess tthhee rree oovveerriieess ooff tthhee eelleemm ss iinn tthhe ff 8800 %% ttoo 1122 %%..

2.3 adiat and stems

2.3. Irradiation facility

The i s were d in The IGA Ma laysia Institute for Nuclear Technology Research (MINT) reactor. Reactor TRIGA II was installed by General Atomic (San Dieg U.S.A) and 19 he react ith a max ady state power of 1 MWth, consists of a circular core containing a circular plate and a graphite assembly rounding the core this reactor there are 40 position annular r s that rotate s wly around the core which used for long irradiation with neutron flux of 4-5× 10ˆ¹² n/cmˆ².sec for long-lived isotopes such as As, Ba, Ce, Cr, Fe f Lu, Sb Tb, Th, U atic transfer system (PTS) used r short n for im countingNa, K and Ca

In case ple, standard solutions and certified reference

aterial were irradiated for a period of 30-60 second on the same position and the cooling time varies

old wire attached to the mple and the third gold ire attached to the last sample to ensure and evaluate any fluctuations in neutron flux.

In case of the long irradiation, each batch which contains the sedim ples, standard solutions, certified rence nd e old wires which were distributed carefully among the batch were irradiated for 6 hours. The c times for first counting varies 3-6 days depending on the dead time of the samples and 3-4 weeks for second counting.

2.3.2 Counting systems After the sediment samples, standard solution rtified r ence materials were irradiated for short and long ion. T he sa analyzed spectroscopically and gamma-ray spectr itted f m sedimen les w d usin ifferent coaxial high

solution hyper-pure germanium spectrometers (HpGe) with energy resolution better than 1.90 KeV r the 1332 KeV gamma-ray line of Co-60, and with relative efficiencies ranging from 10 to 30 %. nergy and efficiency calibration of the gamma spectroscopy systems in the energy range from 60 to 000 KeV have been carried out in the same geometrical configuration used for measuring sediment

irndard s tions for s

ylene vial aand long irrad on were red by evapor filter peat-sealed. M quaalliittyy aassu

r, ttoo ccuracy and orporated inccuracy and ooff gge

lity controurraacc dd pprreecciissiioonn ee IINNAAAA tteec aann rree aassssuurreedd eetthhooiati

ssiati analyzi

hh nn analyzinn fiieedd rreffeerreenne rriiallssa uucchh ass ssooiila iitth eeh

oowwnn ii thhee uu rr IIAAEEAA--SS rrttiiffiieeeerriiaa MM)) wwiitthh cceerr dd aanndd rreeccoommmm vvaall eeccoovveerriieess ooff tth ttss iinn

tto %%.. SSee yy iirrrraaddiiaattiin ii uunn oonnssiissttiinngg oo lldd ((mm,, hh 55..55 mm MMMM)) aalloo h eeaa ff pp

ddaarrdd n tteecchhnniiqq ss ll rraaggee rreessuu rr IIifie rreennccee MM M dd nndd cceenntt e rraannggee oo 66

rIr ion facility counting sy

1

rradiation performe TR rk II at Ma

o, in 1981 82 [10]. T or, w imum stegrid sur

. In ack lo

Co, , H , La, o

, Sc, Sm, , and Zn. and the pneum fo irradiati mediate of short-lived isotopes such as Al, Ti, V, Mn, Mg,

, .

m

of the short irradiation, each sam

from 5-20 minutes for first counting and the second counting after 24 hours for determination of Na and K. For K0-INAA method three gold wires were attached to the top surface of the samples, the first

first sample, second gold wire attached to middle sagw

ent samrefe material a nough g

ooling

s and ce efer irradiat hen, t m e

reples wer

a em ro t samp ere measu g drefoE2

samples using a set of Ba-133 , Co-60 , Co-57, Cs-137, Mn-54 and Am-241 standard sources and at different distance from the detectors.

Gamma-ray spectra emitted from the sediments samples were collected in 8000 channels of the for a p per time period. The different photo peaks of easured spectra were identified and

analyz nd Genie 200 In cas eterm f h s that non-meas IN s in-Elmer SCIEX 0 ed is ea A sappr 20 d a ed ml lo . H m . H d igh e. T e

ed d a ts m icr en n heed ool t a a ts u haple led em d ef rs e nd. T sol sf 0 l a to about 50 mble wat nk ed ea o M enples certified e digestion group to re t cy of the analytical procedures. ppm ulti-elemtion nit a preparations 0, lu

respect ete of io n c The ility na n ye q r Sorm lyz RM A ob m g ole cur r measuremen pared to certif s Mpta

Res Dis

t ed sa giv ble 5 e ropogenic elem p, po en an th group, ective he tab th d on r N ndle a em pm) dry-weigh thr f a aese an m, mum concentr ea t sparison of elem cen ges in grab sed S el hoit o nd e in average s c ter id dity an an herla

ents that identified in ent samCo o, N Sb, S Zn thr gro a ioCu, o, e lower than th tio ted g d tal materials wh tal tio Ba re lower than nt

estimat n cru ater e o s, t nc o Cd are greater than the concentration estimat r mean crustal ma and than ncent av les . e c io ly

times o co ns fo sha ea m israit of Melaka may due to industrial activities

The non-anthropogenic elements that identified in the grab sediment samples were Al, Br, Ca,

Cs, Fe, Hf, K, Mg, Mn, Na, Rb, Ta, Ti, Th, and U. Th total concentrations of Fe, Mn, Al, and Ti are lower than the concentrations estimated for average shales and mean crustal materials, while the total concentrations of Na, K, Mg, Ta, and Ca are lower than the concentration estimated for mean crustal

PC ro med using Gamma Vision a 0 analysis software’s.

e of d ination o eavy metal urable by AA such a Pb, Ni, and Cd, a Perk Elan 600 ICP-MS us for analys of those h vy metals. duplicate mple of a oximately 0-230 mg ry weight w s transferr to a 100 valve Tef n beaker, 3 ml of conc F and 10 l of conc NO3 adde to the we ed sampl The valve eflon beak r was clos and heate t 440 Wat inside a co mercial m owave ov for 15 mi utes, and t n the heat samples c ed to room emperature nd reheated t 600 Wat for 20 min tes. After t t, the sam s were coo to room t perature an the valve T lon beake were open d carefully i fume hoo he clear utions tran erred to 10 ml polyethy ene bottle nd diluted l by dou distilled er. A bla was carri out with ch group f samples. oreover, ough samassu

from IAEA-SOIL-7 reference material was digested with somA 100 he accura

in 5% of 28 m

of 50, 10ents calibration standard

250 ppb solu ric acid w s used for standard so tions ively for d rmination concentrat n calibratio urve.

applicab of the a lytical tech ique emplo d and the uality cont ol of ICP-M was perf ed by ana ing the C , i.e. IAE ’s SOIL-7 tained fro IAEA. In eneral as sh wn in Tab 3, the ac acy of ou ts as com ied value of the CR are acce ble.

2. ults And cussion

Results of he analyz sediment mples are en in Ta 4, Table and Tabl 6 for anth ents grou non-anthro genic elem ts group d rare ear elementsresp ly. T les shows e measure concentrati s in (%) fo Al, Ca, K, a, Fe, Ti a Mg, whi ll other el ents in (p t. The last ee rows o Table 4, T ble 5, and T ble 6 repr nt the me , maximu and mini ation for ch elemen . Table 7, hows com ental con tration ran iments of trait of M aka with t se of Stra f Johor a with thos hale, mean rustal ma ial and gu eline of se iment qual of Canadi d Net nds.

The anthropogenic elem

, Cr, Cu, M the grab sedim

. In the anples were Ag, As, Ba,

up, the totCd, i, Pb, r, V, and opogenic l concentrat ns of Cr, Zn, Ni, C and V ar e concentra ns estima for avera e shales an mean crus ile the to concentra ns of Sr, , and V a the conce ration

ed for mea stal m ials. On th ther hand he total co entrations f As, Ag, , and Sb ed fo terials lower the co ration for erage sha except Sb Finally, th oncentrat n of Pb is approximate two

f the total ncentratio estimated r average les and m ns crustal aterial. Th high concentration of Pb in grab sediment samples from Stsuch as automotive emissions.

e

materials only. On the other hands, Cs, Hf, Rb, Br, Th, and U shows a total concentrations greaterr mean crustal materials

than the concentrations estimated fo .

The rare earth elem ifie en of Melaka were C , L , and Yb. The total concentrations of Eu, Lu, and Sc are lower than the c ns for sha crustal materials. The total concentration of Cr, S r t on e or ta s a y above the concentration ge i o tration of Yb er than the concentrations estimated fo ag d m al m 3. Conclusio

K a newly dev A iv e has been successfully te ca he th t re use of standard solutions is sefu ue, facilitating d n ts andards, the te an als n add ali of cal e.

co n o , As, Ba, Br, Ca o, u, f, K, La, Lu, M o, , Rb, Sb, Sc, S Th , Yb, and Zn were determined in grab s mples of the Strait of Melaka. The total concentration of the most o found lower than the concen esti average shales cr rials except As, Ag, Cd, Sb, Cs, Hf, Rb, Br, Th, U, Yb and Pb.

ents ident d that in the grab sedim t samples Strait of e, Eu, La u, Sc, Smoncentratio estimated average les and mean m is lowe han the c centrations stimated f mean crus l material nd slightl

for avera shales. F nally, the t tal concen is greatr both aver e shales an ean crust aterials.

n

The 0-INAA, eloped NA quantitat e techniqu at MINTsted of its pability. T K0-INAA at does no quire the

a very u l techniq apart from eterminatio of elemen without stchnique c o be a itional qu ty control the analyti procedur

The ncentratio f Ag, Al , Cd, Ce, C Cr, Cs, C Eu, Fe, Hg, Mn, M Na, Ni, Pb m, Sr, Ta, , Ti, U, V

ediment sa f elementstrations mated for and mean ustal mate

Table 1: Geographic coordinates, distance from the offshore and water depth of marine sediment samples

PLE o.

SAMPLE COD

LATITUDE LONGITUDE WATED

Distance from offshore (Km)

SAMN

R E EPTH

(m) 1 C 0 ' N 8.26o 20.343 099o 3W 07A 56' E 9.1 2.96 2 WC07B 06 09.90' N ' E 4.07 o 099 51.40o 9.8 3 WC 06o 15.64' N 7.6099 5o 7' E 8.0 5.93 07C 4 C 0 o N 0.5W 08A 6 10.90' 100 1o 0' E 9.5 8.70 5 WC08B 06 N o 04.94' 100 12.91o ' E 11.0 7.87 6 WC08 o N C 06 01.79' 100 11.52o ' E 7.4 8.39 7 WC09A 05 N o 46.88' 100 10.57o ' E 19.0 21.48 8 WC09B 05o N 100o 14.98 42.43' ' E 7.1 11.11 9 WC09 N 100o 14.11C 05o 37.96' ' E 7.8 11.11

10 o 43.54' N 100o 20.9 10.4 WC10A 04 8' E 26.85WC10B 0 N 100o 22.78' E 23.71 4o 40.52' 11 12.9

12 C 0 N 100o 24.9 4o 38.01' WC10 6' E 11.8 17.7813 WC 0 N ' E 11A 4o 05.85' 100o 36.12 7.6 7.41 14 WC11B 0 N 6.9 4o 00.25' 100o 3 9' E 12.6 10.1915 WC 0 N 9.011C 3o 55.57' 100o 3 3' E 15.2 6.85 16 WC 0 N 1.4 17.3 3o 50.78' 100o 412A 9' E 5.56 17 WC 0 N 3.93o 46.98' 100o 412B 4' E 20.2 8.52

WC12C 0 N 100o 47.5 20.8 3o 42.38' 18 9' E 12.9619 C 0 N 7.23o 21.30' 101o 0W 13A 2' E 12.0 8.33 20 C13B 0 N 8.93o 19.43' 101o 0W 7' E 13.2 9.07 21 WC13C 17.3 03o 17.13' N 101o 11.10' E 4.63 22 WC 7.214A 02o 49.16' N 101o 1 2' E 18.0 2.26 23 WC 0 ' N 6.867' E 2o 40.806 101o 214C 34.2 3.70

WC15A 02o 20.46' N 00.102o 54' E 24 11.9 2.59 25 WC 0 N 1.9 2.41 2o 19.56' 102o 015B 8' E 10.4 26 WC 0 N ' E 2o 18.10' 102o 03.0015C 7.9 2.65 27 WC16A 02 01.06' N 6.0 10.93 o 102o 2 0' E 10.2 28 WC 0 N ' E 1o 59.89' 102o 28.0716B 8.6 9.26 29 WC 01 58.54' N 0.5o16C 102 3o 4' E 6.4 6.85 30 WC17A 01o 49.18' N ' E 4.19 102 43.91o 13.0 31 WC 0 o N 4.8 17B 1 48.84' 102 4o 5' E 14.6 6.1532 WC 0 N 102 46.17C 1 48.00' o o 0' E 16.0 7.33

WC 0 N 103o 05.333 18A 1 38.25' o 0' E 8.0 4.63 WC18B 01 N 103o 06.90o34 37.27' ' E 8.9 4.26 WC18 N o35 C 01o 36.41' 103 08.40' E 5.2 3.89

Table 2. Comparison of concentrations determined in certified reference material (IAEA-SOIL7) witded values for INAA by compar

h certified or recommen ative method and K0-method.

Recovery Measured Value

g/kg (y K0

Recovery )

Measured Value ) iv

Certified & Rm

Element (%) m

bppm)

-Method (%

e mg/kg (ppm

by Comparateco. Value g/kg (ppm)

Method 47000 ± 3500 106 50000 ± 1075 899 5141925 ± 4Al

13.4 ± 0.80 13.82 .5613.63 ± 0 10 4 ± 2.42 103 As 159 ± 32.5 Ba - -

8.32 ± 0.84 - 7 ± 3.5 119 Br 126 205000163000 ± 8500 92 4 150449 ± 1158 ± 17117 Ca

61 ± 6.71 54.6.8377.33 ± 4 4 ± 3.32 89 Ce 104 .73 9.27 ± 08.9 ± 0.89 - Co

60 ± 12.6 69.00 ± 7.33 115 - Cr 5.4 ± 0.76 - 4.31 ± 0.44 80 Cs 11 ± 1.98 - - Cu

- - 3.9 ± 1.05 Dy 118 1.18 ± 0.02 - 1.0 ± 0.2 Eu 106 27236 ± 1670 - 25700 ± 550 Fe 116 5.94.23 ± 0.69 4.85 ± 05.1 ± 0.36 Hf 121 14700 199 ± 2521 98 11898 ±12100 ± 700 K 102 28.7 .22 4 ± 3.68 70 19.46 ± 328 ± 1.12 La

- 90 030.27 ± 0.0.3 ± 0.15 Lu - 928 8510364 ± 11300 ± 400 Mg

114 718.5 4.3 0 ± 6.47 965 605.63 ± 2631 ± 25 Mn 2400 ± 100 2419 ± 115 27701 20 ± 99.72 10Na

- - 30 ± 6 Nd - 94 47.87 ± 4.18 51 ± 4.59 Rb

118 2.011 14 ± 0.30 101.72 ± 0.1.7 ± 0.2 Sb 114 9.522 ± 0.46 10 8.47 ± 0.668.3 ± 1.08 Sc

- 114 5 5.84 ± 0.515.1 ± 0.36 Sm - 0.8 ± 0.2 Ta -

0.6 ± 0.19 Tb - 75 110.45 ± 0.7.558 53 Th 8.2 ± 1.07 8.02 ± 0. 9 ± 0.98 92

3000 ± 550 - - - Ti 2.6 ± 0.55 - 121 29 3.15 ± 0. U

68.67 .85V 2 ± 5.73 9 64.10 ± 166 ± 7.26 104 2.4 ± 0.36 2.59- ± 0.23 - 108 Yb

6 110.08 ± 13.4104 ± 6.24 107 - Zn - - 185 ± 11.1 - Zr

Table 3. Comparison of con s in efe eri O

ertified or rec alues for ICP-M

EA

centration determined standard r rence mat al (IAEA-S IL7) withc ommended v S results

IA -SOIL7 Element Cert. or Rec.

Value ) )

Valg

cov(%)

95% Con. Interval

Average mg/k

ue Re ery

mg/kg (ppm mg/kg (ppmZn 104 ± 6.24 3.8 13101-113 144.00 ± 4 8 Sr 108 ± 5.4 2.0 77 103-114 83.43 ± 0 Ti 3000 ± 550 2600-3700 3201 ± 124 106 Ni 26 ± 8 6 ± 1.25 133 21-37 34.6Cu 11 ± 1.98 0.39 139-13 14.44 ± 1 As 13.4 ± 0.80 12.5-14.2 14.24 ± 0.27 106 Ag ** ** 0.31 ± 0.01 - Cd 1.3 ± 0.80 1.1-2.7 0.84 ± 0.01 65 Pb 60 ± 7.8 55-71 68.73 ± 0.63 114 Mo 2.5 ± 2.1 0.9-5.1 1.73 ± 0.03 69 Mn 631 ± 25 604-650 643.60 ± 15.25 102 Ba 159 ± 32.5 131-196 115.23 ± 1.39 72

Table 4. Concentrations of anthropogenic elements (ppm dry-weight) in grab sediment samples from Strait oMelaka

f

Location pp pp pm ppm) *Mo (pp ppm pm pm) *Ag ( m) *Cd ( m) Cr (p ) *Cu ( m) *Pb ( ) Zn (p ) *Ni (p

WC07A OD ± 0. 17.87 14.90 ± 0. 0.0 ± 1 12 ± 1.11 L 0.03 01 63.60 ± 84 1.00 ± 3 42.09 .77 49.50 ± .24 31.65

WC07B LOD ± 0. 19 ± 0 0.0 ± 1.78 57.46 ± 12. ± 1.43 0.08 01 69.84 ± .96 13.32 .75 1.50 ± 5 39.35 28 40.10

WC07C ± 0.0 0.0 17 ± 0 0.0 ± 2. 13 ± 1.38 0.43 1 0.21 ± 17 70.61 ± .47 14.65 .93 0.90 ± 3 54.74 17 70.68 ± .64 39.60

WC08A ± 0.0 ± 0. ± 5 ± 0 0.0 ± 1 15 ± 1.09 0.21 1 0.27 01 46.69 .86 16.60 .88 1.00 ± 3 39.19 .68 63.32 ± .02 28.90

WC08 ± 0.0 ± 0.01 86.49 ± 8. ± 1 0.0 ± 2. 17 ± 1.53 B 0.40 1 0.29 87 18.51 .15 1.55 ± 6 55.85 24 72.36 ± .70 36.25

WC08C ±0.0 0. ± 8. ± 0 0.03 53 ± 2.3 14 ± 1.23 01 65.54 1.00 3 0.27 ± 71 13.05 .65 1.00 ± 51. 5 62.16 ± .82 31.05

WC09A ±0.01 0.30 ± 0. 17 ± 0 0.03 90 ± 1. 9. ± 1.32 0.18 01 65.07 ± .70 16.55 .78 1.00 ± 41. 92 75.58 ± 81 40.50

WC09 ± 0.0 ± 0. 15.67 13.90 ± 0. 0.03 30 ± 2. 12 ± 1.28 B 0.41 1 0.22 01 61.58 ± 71 1.00 ± 52. 16 80.38 ± .38 33.00

WC09C ± 0.0 ± 0 14 ± 0 0.0 ± 2 11.66 23.05 ± 1.21 0.10 1 0.28 .01 47.36 ± .99 10.25 .59 1.15 ± 4 47.76 .32 50.91 ±

WC10A ± 0.0 ± 0.01 59.88 ± 5. ± 0 0.0 ± 2 4. ± 1.33 0.28 1 0.25 39 12.21 .74 0.95 ± 3 59.65 .44 44.75 ±1 17 25.30

WC10 ± 0.0 ± 0.01 55.87 ± 5.64 12.00 ± 0. 0.07 57.73 ± 2. 4. ± 1.57 B 0.54 1 0.27 86 2.00 ± 31 60.57 ±1 29 37.00

WC10C ± 0.0 ± 0. ± 5. 0. 0.0 ± 2. 18 ± 1.36 0.45 2 0.25 01 57.85 44 15.40 ± 1.24 1.00 ± 3 57.04 28 107.80 ± .24 36.10

WC11A 0.30 ± 0.0 ± 0 4. ± 0.61 0.90 ± 0.0 ± 2. 12 ± 1.45 1 0.20 .01 45.63 ± 78 12.90 3 64.50 48 60.42 ± .90 34.50

WC11 ± 0.0 ± 0 5. ± 0 0.0 ± 2. 16.62 34.80 ± 1.44 B 0.44 2 0.47 .01 48.94 ± 09 13.88 .72 1.00 ± 3 61.80 54 97.47 ±

WC11C ± 0.0 ± 0.01 52.96 ± 5. ± 0 0.0 ± 2.44 92.30 ± 19. ± 1.25 0.33 1 0.16 46 15.10 .83 1.00 ± 3 64.77 37 29.00

WC12A ± 0.01 0.09 ± 0. ± 4. ± 0 0.03 34.85 ± 1. 15 ± 1.40 0.32 01 50.07 58 15.10 .87 1.00 ± 97 79.47 ± .52 26.80

WC12 ± 0.0 ± 0. ± 4. ± 0.74 0.90 ± 0.0 ± 1. 13 ± 1.47 B 0.30 1 0.10 01 45.32 07 13.30 3 34.70 81 62.52 ± .21 25.90

WC12C ± 0.0 ± 0. ± 4.62 16.86 ± 1. 0.0 ± 2 14.67 26.40 ± 1.64 0.33 1 0.12 01 45.30 20 1.00 ± 3 52.70 .09 65.23 ±

WC13A ± 0.0 ± 0.01 57.17 ± 5. ± 0. 0.0 ± 1 12 ± 1.26 0.35 1 0.10 76 9.29 76 1.30 ± 5 34.40 .80 81.41 ± .36 23.10

WC13 ± 0.0 ± 0. ± 7. ± 0 0.0 ± 1. 14 ± 1.34 B 0.31 1 0.19 01 65.94 08 14.10 .84 1.00 ± 3 42.80 79 97.34 ± .52 27.00

WC13C ± 0.0 ± 0 4. ± 0.59 1.00 ± 0.0 ± 1. 12 1.04 0.23 1 0.06 .01 31.85 ± 33 7.80 3 37.46 77 86.91 ± .10 20.30 ±

WC14A ± 0.0 ±0.0 ± 6.75 8.30 ± 0. 0.0 ± 1. 7. ± 0.72 0.20 1 0.10 1 77.29 56 0.30 ± 1 32.70 35 57.01 ± 87 10.00

WC14C ± 0.0 ± 0. ± 3. ± 0. 0.1 ± 1. 7. ± 0.90 0.30 1 0.09 01 29.39 76 8.81 53 3.00 ± 1 34.60 37 34.71 ± 19 13.80

WC15A OD ± 0. ± 4. ± 0 0.03 45.46 ± 1. 7. ± 1.21 L 0.11 01 31.62 07 11.70 .71 1.00 ± 87 32.04 ± 01 23.00

WC15 ± 0.0 ± 0. ± 5. ± 1 0.0 ± 1. 11 ± 1.25 B 0.50 1 0.14 01 52.72 78 18.70 .18 1.00 ± 3 51.76 91 79.23 ± .50 25.30

WC15C ± 0.0 ± 0. ± 3. ± 0. 0.0 ±1. 6.94 18.10 ± 0.95 0.30 1 0.20 01 35.45 91 9.90 52 1.10 ± 4 34.50 42 42.43 ±

WC16A 0.39 ± 0.0 ± 0.01 47.76 ± 4. ± 0.86 1.00 ± 0.0 ± 1 8. ± 0.92 1 0.13 51 12.92 3 40.00 .58 74.93 ± 85 19.70

WC16 ± 0.0 ± 0 7. ± 1 0.0 ± 1 12 ±1.44 B 0.53 2 0.11 .01 56.11 ± 06 21.40 .39 1.00 ± 4 29.60 .60 89.56 ± .81 28.10

WC16C 0.37 ± 0.0 D 78.64 ± 5. ± 0.56 1.00 ± 0.0 ± 1 11 ± 0.94 1 LO 95 12.10 3 25.64 .24 119.17 ± .23 20.00

WC17A ± 0.01 LOD 4.58 10.20 ± 0. 0.03 20.60 ± 1. 13 ± 0.97 57.71 ± 0.27 67 1.00 ± 32 97.17 ± .17 20.10

WC17B 0.50 ± 0.0 D 4. ± 0.74 0.90 ± 0.0 ± 1. 16 ± 0.96 57.80 ±2 LO 45 12.30 3 24.40 11 110.50 ± .55 20.50

WC17C ± 0.0 D 5.21 13.67 ± 0. 0.0 ± 1 15 ± 1.11 0.30 1 LO 59.26± 94 1.00 ± 3 21.50 .28 113.54 ± .67 21.30

WC18A ± 0.0 ± 0. ± 4. ± 0 0.0 ±1. 10 ± 1.01 0.25 1 0.13 01 42.35 04 15.36 .80 0.60 ± 2 20.80 33 62.91 ± .38 18.70

WC18 ± 0.0 ± 0. ± 5. ± 0 0.0 ± 1. 9. ± 1.05 B 0.40 1 0.02 01 50.00 05 12.95 .71 1.00 ± 3 26.49 31 66.75 ± 87 24.55

WC18C ± 0.01 LOD 48 ± 2.99 47 ± 0.59 04 .95 ± 1.23 22 .30 ± 1.42 0.31 35. 9. 1.05 ± 0. 25 55.67 ± 8. 24

Mean 0.36 0.17 3 .36 41.75 8 79 54.4 13 1.09 72.9 26.

Max. 00 ±0.0 ± 0. ± 8. ± 1 0.1 ± 2. 11 1.32 1. 3 0.47 01 86.49 87 21.40 .39 3.00 ± 1 64.77 44 119.17 ± .23 40.5 ±

Min. 0.10 ± 0.01 0.02 ± 0.01 29.39 ± 3.76 7.80 ± 0.59 0.30 ± 0.01 20.60 ± 1.32 32.04 ± 7.01 10.00 ± 0.72

*Analysis by ICP-MS; LOD = Lower Than Limit of Detection

Table 4. (cont.) Concentrations of anthropogenic elements (ppm dry-weight) in grab sediment samples from Strait of Melaka

Location

Sb (ppm) As (ppm) *Sr (ppm) *Ba (ppm) Co (ppm) V (ppm) WC07A 0.92 ± 0.20 5.61 ± 3.34 61.50 ± 2.61 LOD 5.80 ± 0.85 45.84 ± 7.56

WC07B 1.20 ± 0.21 8.16 ± 5.22 23.10 ± 1.05 LOD 7.04 ± 1.08 52.51 ± 8.35

WC07C .12 55.32 ± 9.13 1.42 ± 0.22 11.04 ± 5.79 30.90 ± 1.27 49.00 ± 0.67 7.21 ± 1

WC08A 1.74 ± 0.16 21.87 ± 3.04 264.30 ± 11.95 33.20 ± 0.30 4.64 ± 0.61 50.82 ± 8.52

WC08B 1.43 ± 0.14 18.06 ± 0.92 26.50 ± 1.21 61.00 ± 0.63 6.80 ± 1.59 72.99 ± 7.93

WC08C 1.56 ± 0.16 14.05 ± 1.15 43.90 ± 2.29 62.00 ± 0.69 5.51 ± 1.49 51.49 ± 6.78

WC09A 1.45 ± 0.15 4.25 ±0.70 378.50 ± 17.26 128.35 ± 0.99 10.16 ±1.50 51.37 ± 7.96

WC09B 13 1.46 ± 0.19 11.00 ± 5.41 20.80 ± 0.83 41.00 ± 0.31 7.05 ± 1.13 64.57 ± 10.

WC09C 1.84 ± 0.13 2.72 ± 0.40 344.10 ± 14.48 83.10 ± 0.98 10.01 ± 1.30 50.58 ± 5.97

WC10A 0.77 ± 0.19 10.39 ± 0.89 23.60 ± 1.13 41.50 ± 0.32 7.61 ± 1.36 64.69 ± 9.21

WC10B 0.62 ± 0.19 8.29 ± 0.80 39.40 ± 1.66 64.00 ± 0.69 7.43 ± 1.48 67.71 ± 8.63

WC10C LOD 8.57 ± 0.82 38.90 ± 1.62 62.00 ± 0.65 7.36 ± 1.10 72.98 ± 7.74

WC11A 1.78 53.0.79 ± 0.17 12.29 ± 0.71 79.80 ± 3.63 90.00 ± 0.75 10.53 ± 36 ± 9.23

WC11B 0.63 ± 0.13 7.51 ± 0.62 55.30 ± 2.21 92.00 ± 0.78 7.42 ± 1.08 55.49 ± 9.78

WC11C 0.71 ± 0.22 6.04 ± 0.51 39.90 ± 1.72 51.00 ± 0.39 8.39 ± 1.55 62.81 ±10.13

WC12A 0.54 ± 0.15 5.95 ± 0.49 37.10 ± 1.84 51.00 ± 0.60 10.25 ± 0.89 70.30 ± 9.63

WC12B 0.52 ±0.11 4.14 ± 0.38 51.00 ± 2.13 61.20 ± 0.87 8.06 ± 0.78 58.15 ± 8.73

WC12C 0.41 ± 0.12 5.59 ± 0.49 73.80 ± 3.45 83.00 ± ± 0.75 6.38 ± 0.83 55.15 ± 9.65

WC13A 0.58 ± 0.08 7.44 ± 1.97 17.40 ± 0.91 43.50 ± 0.42 9.55 ± 1.10 97.43 ± 7.68

WC13B 0.68 ±0.07 6.78 ± 2.12 23.70 ±1.09 47.00 ± 0.46 9.46 ± 0.83 79.37 ± 7.96

WC13C 0.55 ± 0.12 4.80 ± 1.37 71.00 ± 3.30 113.00 ± 0.91 8.49 ± 0.72 35.93 ± 6.95

WC14A 0.92 ± 0.10 8.05 ± 0.94 12.40 ±0.74 51.00 ± 0.60 8.39 ± 0.83 39.42 ± 7.98

WC14C 0.47 ± 0.07 4.76 ± 0.77 10.20 ±0.63 33.00 ± 0.27 4.76 ± 0.48 41.36 ± 8.57

WC15A 0.68 ± 0.37 5.98 ± 1.33 104.90 ± 4.58 81.00 ± 1.22 5.65 ± 0.51 54.31 ± 7.96

WC15B 0.71 ± 0.50 8.37 ± 1.80 24.20 ± 1.18 43.00 ± 0.39 9.75 ± 0.82 43.02 ± 7.23

WC15C 0.42 ± 0.21 4.38 ± 1.25 53.00 ± 2.54 89.10 ± 0.88 5.68 ± 0.49 32.58 ± 5.95

WC16A 0.57 ± 0.27 9.25 ± 1.90 23.20 ± 0.96 47.00 ± 0.35 9.47 ± 0.67 93.46 ± 6.37

WC16B 0.99 ± 0.11 8.34 ± 1.08 44.90 ± 2.53 92.90 ± 6.98 12.63 ± 1.11 115.00 ± 5.76

WC16C 1.16 ± 0.14 12.58 ± 3.75 19.70 ± 0.94 47.00 ± 1.15 12.88 ± 0.94 71.43 ± 6.87

WC17A 0.85 ± 0.07 9.46 ± 1.14 16.70 ± 0.94 37.00 ± 0.79 11.69 ± 0.84 83.11 ± 6.31

WC17B 3.99 ± 1.30 10.60 ± 1.17 21.10 ± 10.4 50.30 ± 0.97 11.98 ± 0.99 68.38 ± 7.73

WC17C LOD 9.53 ± 0.83 17.10 ± 0.88 40.00 ± 0.31 12.26 ± 0.89 80.97 ± 6.59

WC18A 1.64 ± 0.49 8.73 ± 0.82 33.30 ± 1.87 62.60 ± 0.48 8.46 ± 0.79 63.28 ± 8.64

WC18B 2.00 ± 1.13 7.60 ± 0.71 30.10 ± 1.42 66.00 ± 0.76 8.68 ± 0.75 65.05 ± 7.89

WC18C 1.06 ± 0.86 10.03 ± 0.78 99.60 ± 4.19 48.70 ± 0.40 9.07 ± 0.82 57.37 ± 8.67

Mean 1.07 8.63 64.43 61.98 8.47 62.22

Max. 3.99 ± 1.30 21.87 ± 3.04 378.50 ± 17.26 128.35 ± 0.99 12.88 ± 0.94 115.00 ± 5.76

Min. 0.41 ± 0.12 2.72 ± 0.40 10.20 ± 0.63 33.00 ± 0.27 4.64 ± 0.61 32.58 ± 5.95


Table 5. Con ntrations of non-anthropogenic elements (ppm dry-weight) in grab sediment samples from Strait of Melaka

ce

L)

ocation Cs (ppm) Fe (%) Hf (ppm) K (%) Mg (%) Mn (ppm) Na (%) Al (%

W 36 C07A 9.00 ± 1.12 1.84 ± 0.10 6.45 ± 1.12 1.53 ± 0.20 1.49 ± 0.32 253 ± 27.28 2.32 ± 0.24 4.75 ± 0.

WC07B 11.79 ± 1.25 2.72 ± 0.28 7.79 ± 1.21 1.69 ± 0.11 2.43 ± 0.47 260 ± 27.13 2.61 ± 0.27 7.83 ± 0.53

WC 48 07C 12.25 ± 1.15 2.63 ± 0.22 7.43 ± 0.63 1.60 ± 0.14 2.91 ± 0.41 293 ± 30.38 3.04 ± 0.29 6.80 ± 0.

WC08A 7.26 ± 0.69 1.88 ± 0.21 5.06 ± 0.49 0.87 ± 0.11 1.66 ± 0.39 148 ± 19.62 1.99 ± 0.20 3.84 ± 0.30

WC ± 0.63 08B 14.94 ± 1.96 3.00 ± 0.26 5.21 ± 1.12 1.93 ± 0. 21 2.31 ± 0.45 231 ± 33.20 3.23 ± 0.33 9.39

WC08C 10.48 ± 1.30 2.39 ± 0.23 9.68 ± 0.69 1.49 ± 0.23 1.69 ± 0.34 188 ± 20.75 2.45 ± 0.23 6.68 ± 0.46

WC 0.56 09A 7.81 ± 0.69 2.89 ± 0.38 5.26 ±0.57 1.61 ± 0.20 1.64 ± 0.38 1013 ± 99.12 2.12 ± 0.09 7.33 ±

W 1.59 ± 0.13 1.58 ± 0.33 239 ± 28.63 2.70 ± 0.26 8.29 ± 0.55 C09B 11.88 ± 1.13 3.11 ± 0.28 6.80 ± 0.80

WC09C 6.55 ± 0.72 1.89 ± 0.25 9.25 ± 0.97 1.25 ± 0.09 1.31 ± 0.31 233 ± 26.89 2.15 ± 0.21 7.60 ± 0.47

WC 0.55 10A 11.71 ± 1.50 3.12 ± 0.29 7.67 ± 0.58 1.64 ± 0.12 1.43 ± 0.29 385 ± 39.12 2.73 ± 0.06 8.05 ±

WC10B 0.29 6.98 ± 0.57 1.57 ± 0.14 1.33 ± 0.29 379 ± 39.58 2.81 ± 0.28 8.85 ± 0.10.82 ± 1.28 2.81 ± 67

W .64 C10C 11.59 ± 1.51 3.09 ± 0.30 6.61 ± 0.66 1.68 ± 0.13 2.08 ± 0.44 420 ± 43.58 3.49 ± 0.34 9.49 ± 0

WC11A 9.90 ± 1.29 4.43 ± 0.40 9.14 ± 0.64 1.69 ± 0.15 1.47 ± 0.24 401 ± 38.41 2.13 ± 0.21 8.86 ± 0.57

WC 54 11B 10.43 ± 1.38 2.48 ± 0.25 9.67 ± 0.58 1.66 ± 0.12 2.22 ± 0.73 402 ± 39.03 2.40 ± 0.23 8.14 ± 0.

WC11C 10.72 ± 1.37 2.68 ± 0.25 5.95 ± 0.57 1.60 ± 0.09 2.31 ± 0.57 555 ± 58.51 3.79 ± 0.09 9.42 ± 0.65

WC 0.71 12A 11.23 ± 1.39 2.66 ± 0.25 4.56 ± 0.50 1.62 ± 0.15 2.87 ± 0.60 502 ± 61.30 3.12 ± 0.43 9.24 ±

WC .84 4.71 ± 0.45 1.57 ± 0.16 2.14 ± 0.45 506 ± 52.72 2.80 ± 0.38 8.42 ± 0.64 12B 9.49 ± 1.06 2.49 ± 0

WC12C 9.22 ± 1.13 2.20 ± 0.20 4.91 ± 0.36 1.49 ± 0.15 1.08 ± 0.57 409 ± 43.83 2.78 ± 0.35 7.41 ± 0.58

WC ± 0.84 13A 12.00 ± 1.12 2.76 ± 0.09 8.47 ± 0.65 1.79 ± 0.11 1.60 ± 0.35 369 ± 40.64 2.47 ± 0.25 11.58

WC13B 14.15 ± 1.50 3.32 ± 0.11 8.44 ± 0.57 1.59 ± 0.09 1.84 ± 0.50 384 ± 42.81 2.90 ± 0.30 11.79 ± 0.65

WC .32 13C 6.48 ± 0.70 3.65 ± 0.12 14.03 ± 0.77 1.40 ± 0.19 1.47 ± 0.35 302 ± 36.39 1.26 ± 0.18 6.20 ± 0

WC14A 26.91 ± 1.12 0.97 ± 0.35 0.81 ± 0.21 520 ± 49.82 1.01 ± 0.10 4.22 ± 0.32 7.21 ± 0.86 2.41 ± 0.07

WC14C 5.34 ± 0.67 1.32 ± 0.04 9.72 ± 0.55 1.11 ± 0.10 0.65 ± 0.28 184 ± 24.42 1.41 ± 0.13 4.03 ± 0.30

WC15A 6.00 ± 0.86 1.74 ± 0.06 8.49 ± 0.48 0.93 ± 0.37 1.44 ± 0.31 310 ± 31.62 1.15 ± 0.12 6.76 ± 0.59

WC15B 10.01 ± 1.27 2.71 ± 0.09 6.37 ± 0.39 1.53 ± 0.12 1.53 ± 0.22 317 ± 35.77 2.37 ± 0.23 6.84 ± 0.43

W 0.37 C15C 7.41 ± 0.74 1.58 ± 0.05 9.40 ± 0.54 1.24 ± 0.11 1.14 ± 0.30 247 ± 27.48 1.14 ± 0.15 7.15 ±

WC16A 9.65 ± 0.77 2.44 ± 0.07 6.18 ± 0.33 1.52 ± 0.14 1.92 ± 0.42 297 ± 34.76 1.95 ± 0.23 10.39 ± 0.84

WC 93 16B 11.22 ± 1.32 3.10 ± 0.10 6.08 ± 0.51 1.70 ± 0.21 2.45 ± 0.57 326 ± 37.12 2.32 ± 0.23 12.90 ± 0.

WC16C 10.83 ± 1.15 3.86 ±0.11 7.42 ± 0.54 1.83 ± 0.19 3.13 ± 0.47 332 ± 38.23 2.49 ± 0.29 8.49 ± 0.59

WC17A 9.31 ± 0.94 3.08 ± 0.11 6.49 ± 0.49 1.30 ± 0.11 2.30 ± 0.39 336 ± 40.90 2.34 ± 0.28 9.69 ± 0.74

WC17B 22 ± 1.01 3.42 ± 0.10 6.69 ± 056 0.93 ± 0.08 1.70 ± 0.42 330 ± 39.11 2.24 ±0.26 8.35 ± 0.61 10.

WC17C 10.76± 1.03 3.37 ± 0.11 7.21 ± 0.63 1.85 ± 0.18 2.11 ± 0.63 373 ± 45.97 2.83 ± 0.33 8.90 ± 0.64

WC18A 6.55 ± 0.81 2.68 ± 0.08 7.75 ± 0.46 1.11 ± 0.21 1.56 ± 0.43 272 ± 35.94 1.54 ± 0.18 5.99 ± 0.52

WC18B 7.81 ± 0.93 2.58 ± 0.07 9.34 ± 0.63 1.03 ± 0.22 1.87 ± 0.48 238 ± 31.20 1.90 ± 0.22 7.87 ± 0.63

WC18C 4.94 ±0.56 2.94 ± 0.09 9.93 ± 0.49 0.79 ± 0.23 0.92 ± 0.26 302 ± 34.13 1.03 ± 0.12 6.47 ±0.47

Mean 9.63 2.72 8.06 1.45 1.78 350 2.31 7.94

Max. 14.94 ± 1.96 4.43 ± 4.01 26.91 ± 1.12 1.93 ± 0.21 3.13 ± 0.47 1013 ± 99.12 3.79 ± 0.09 12.9 ± 0.93

Min. 4.94 ±0.56 1.32 ± 0.44 4.56 ± 0.50 0.79 ± 0.23 0.65 ± 0.28 148 ± 19.62 1.01 ± 0.10 3.84 ± 0.30

Table 5. (cont.) Concentrations of non-anthropogenic elements (ppm dry-weight) in grab sediment samples from Strait of Melaka

Location

Rb (ppm) Ca (%) Br (ppm) Ta (ppm) Ti (%) Th (ppm) U (ppm) *

WC07A 120.79 ± 32.11 1.25 ± 0. 01 20.35 ± 2.45 7.30 ± 1.12 23 124.72 ± 2.95 1.23 ± 0.28 0.45 ± 0.

WC07B 142.03 ± 2.87 8.70 ± 1.67 ± 38.53 1.18 ± 0.24 215.13 ± 8.70 1.54 ± 0.28 0.32 ± 0.02 22.10

WC07C 115.34 ± 2.76 7.71 ± 1.60 ± 33.65 1.20 ± 0.27 226.83 ± 9.27 1.46 ± 0.30 0.31 ±0.02 21.40

WC08A 73.92 ± 21.09 15.13 ± 0.98 318.99 ± 13.56 1.09 ± 0.48 0.24 ± 0.02 13.46 ± 1.62 14.21 ± 1.87

WC08B 153.17 ± 38.69 0.96 ± 0.27 167.62 ± 5.71 1.93 ± 0.35 0.32 ± 0.02 23.50 ± 2.48 10.03 ± 1.31

WC08C 83.80 ± 21.22 1.54 ± 0.32 188.36 ± 8.76 1.44 ± 0.57 0.28 ± 0.02 18.56 ± 1.72 9.43 ± 0.96

WC09A 109.52 ± 32.54 8.57 ± 0.69 110.85 ± 4.04 1.18 ± 0.51 0.25 ± 0.03 17.22 ± 2.24 17.09 ± 2.19

WC09B 129.05 ± 40.70 1.83 ± 0.26 134.09 ± 4.84 1.85 ± 0.77 0.37 ± 0.02 25.46 ± 2.05 9.86 ± 1.24

WC09C 77.09 ± 27.78 11.16 ± 0.85 82.50 ± 2.00 1.60 ± 0.59 0.25 ± 0.02 17.25 ± 1.78 10.80 ± 1.43

WC10A 104.96 ± 18.59 1.21 ± 0.26 169.49 ± 5.37 1.56 ± 0.39 0.33 ± 0.03 28.56 ± 1.96 4.92 ± 0.93

WC10B 106.45 ± 17.97 1.37 ± 0.26 135.89 ± 4.14 1.72 ± 0.43 0.37 ± 0.03 26.80 ± 1.86 4.19 ± 1.56

WC10C 107.15 ± 18.29 0.87 ± 0.26 178.95 ± 6.06 < 0.90 0.42 ± 0.03 28.04 ± 2.00 6.51 ± 1.54

WC11A 95.85 ± 16.16 2.23 ± 0.38 111.03 ± 6.40 1.58 ± 0.42 0.27 ± 0.02 27.91 ± 1.86 5.51 ± 1.62

WC11B 104.71 ± 15.17 2.33 ± 0.32 128.28 ± 2.98 1.40 ± 0.35 0.30 ± 0.02 24.60 ± 1.84 5.89 ± 1.14

WC11C 97.67 ± 13.33 2.15 ± 0.41 140.96 ± 5.21 LOD 0.31 ± 0.01 26.74 ± 1.77 4.16 ± 1.41

WC12A 88.59 ± 12.66 2.13 ± 0.38 105.08 ± 3.24 LOD 0.31 ± 0.02 25.86 ± 1.83 3.00 ± 0.99

WC12B 92.09 ± 16.24 2.79 ± 0.41 86.50 ± 3.03 1.35 ± 0.35 0.27 ± 0.02 22.76 ± 1.57 3.80 ± 0.89

WC12C 68.77 ± 11.07 LOD 146.80 ± 3.54 LOD 0.31 ± 0.02 19.46 ± 1.34 5.18 ± 0.69

WC13A 134.38 ± 38.21 0.76 ± 0.21 129.22 ± 6.73 1.75 ± 0.27 0.30 ± 0.02 26.65 ± 1.81 4.48 ± 1.10

WC13B 163.71 ± 47.04 0.77 ± 0.25 148.13 ± 7.37 1.78 ± 0.31 0.35 ± 0.03 30.28 ± 2.31 4.10 ± 1.12

WC13C 131.19 ± 32.42 1.91 ± 0.29 54.54 ± 3.30 1.33 ± 0.23 0.23 ± 0.01 23.36 ± 1.65 4.39 ± 1.10

WC14A 71.05 ± 12.41 0.22 ± 0.11 44.62 ± 1.60 1.78 ± 0.32 0.27 ± 0.02 37.38 ± 2.09 9.39 ± 1.69

WC14C 70.96 ± 10.95 0.73 ± 0.24 37.55 ± 1.42 1.10 ± 0.32 1.11 ± 0.07 12.26 ± 0.75 2.73 ± 0.96

WC15A 119.90 ± 31.70 1.93 ± 0.36 45.60 ± 6.40 5.96 ± 0.77 0.68 ± 0.05 18.82 ± 1.14 6.14 ± 1.03

WC15B 177.29 ± 45.10 1.42 ± 0.31 97.10 ± 5.09 1.34 ± 0.19 0.51 ± 0.04 19.26 ± 1.27 3.91 ± 0.93

WC15C 96.19 ± 28.58 1.82 ± 0.29 45.29 ± 2.46 0.95 ± 0.14 0.28 ± 0.02 14.66 ± 1.08 3.35 ± 0.94

WC16A 157.00 ± 41.35 1.31 ± 0.25 90.00 ± 4.03 1.15 ± 0.45 0.33 ± 0.02 18.05 ± 1.14 3.40 ± 0.89

WC16B 156.53 ± 40.61 1.21 ± 0.26 102.57 ± 4.29 1.36 ± 0.45 0.30 ± 0.02 19.80 ± 0.67 4.56 ± 1.12

WC16C 91.99 ± 13.12 1.01 ± 0.25 144.39 ± 8.04 1.54 ± 0.37 0.34 ± 0.03 30.93 ± 1.56 7.01 ± 0.98

WC17A 103.34 ± 18.91 1.34 ± 0.31 94.43 ± 3.51 1.17 ± 0.38 0.29 ± 0.02 21.73 ± 1.27 4.20 ± 1.06

WC17B 147.13 ± 35.04 1.15 ± 0.30 97.53 ± 4.27 1.85 ± 0.92 0.34 ± 0.02 25.06 ± 1.27 6.53 ± 1.07

WC17C 132.14 ± 27.17 0.86 ± 0.27 103.31 ± 5.68 1.75 ± 0.86 0.31 ± 0.02 26.52 ± 1.34 4.59 ± 1.10

WC18A 90.56 ± 24.73 1.59 ± 0.34 82.24 ± 23.74 1.22 ± 0.81 0.27 ± 0.02 18.86 ± 1.27 5.68 ± 0.93

WC18B 100.94 ± 24.93 1.28 ± 0.31 88.91 ± 6.40 1.51 ± 0.75 0.34 ± 0.03 20.12 ± 1.40 6.67 ± 1.21

WC18C 75.25 ± 21.40 3.19 ± 0.47 42.80 ± 13.41 1.30 ± 0.58 0.26 ± 0.02 13.26 ± 0.97 6.23 ± 0.97

Mean 111.07 2.36 120.58 1.61 0.35 22.49 6.45

Max. 177.29 ± 45.10 15.13 ± 0.98 318.99 ± 13.56 5.96 ± 0.77 1.11 ± 0.07 37.38 ± 2.09 17.09 ± 2.19

Min. 68.77 ± 11.07 0.22 ± 0.11 37.55 ± 1.42 0.95 ± 0.14 0.23 ± 0.01 12.26 ± 0.75 2.73 ± 0.96


Table 6. Rare earth elements concentrations (ppm dry-weight) in grab sediment samples from Strait of Melaka

Sm (ppm) Ce (ppm) Eu (ppm) La (ppm) Lu (ppm) Sc (ppm) Yb (ppm)

WC07A 5.74 ± 0.50 75.92 ± 5.68 0.90 ± 0.55 34.04 ± 4.66 0.88 ± 0.30 7.39 ± 0.50 2.80 ± 0.47

WC07B 6.71 ± 0.60 77.68 ± 4.56 1.05 ±0.11 43.54 ± 4.78 1.29 ± 0.42 10.91 ± 0.82 4.02 ± 0.67

WC07C 6.47 ± 0.57 89.25 ± 6.13 1.07 ± 0.70 43.66 ± 4.87 1.13 ± 0.37 10.87 ± 0.81 4.04 ± 0.85

WC08A 4.40 ± 0.39 51.23 ± 4.40 0.71 ± 0.13 103.45 ± 9.67 0.29 ± 0.08 6.47 ± 0.51 6.15 ± 0.84

WC08B 6.11 ± 0.54 96.91 ± 7.51 1.09 ± 0.49 69.94 ± 5.69 0.08 ± 0.03 11.92 ± 0.96 4.73 ± 0.82

WC08 6.17 ± 0.55 89.68 ± 7.64 1.07 ± 0.12 70.19 ± 7.38 0.20 ± 0.06 8.90 ± 0.66 5.34 ± 0.87 C WC09A 6.32 ± 0.58 65.35 ± 5.30 1.18 ± 0.12 98.66 ± 8.63 LOD 8.48 ±0.72 6.56 ± 0.91

WC09B 6.63 ± 0.59 97.98 ± 8.61 1.28 ± 0.24 68.05 ± 5.97 LOD 11.18 ± 0.84 4.94 ± 0.85

WC09C 4.38 ± 0.39 77.24 ± 6.53 1.00 ± 0.46 64.56 ± 7.39 LOD 6.54 ± 0.52 5.52 ± 0.93

WC10A 8.75 ± 0.78 106.82 ± 6.80 0.99 ± 0.20 48.13 ± 6.97 0.34 ± 0.13 12.71 ± 1.47 6.36 ± 1.36

WC10B 7.75 ± 0.68 90.2 ± 6.54 1.10 ± 0.13 44.58 ± 6.24 0.28 ± 0.11 12.66 ± 1.53 3.33 ± 0.79

WC10C 7.26 ± 0.64 107.58 ± 7.02 1.05 ± 0.14 46.34 ± 6.56 0.43 ± 0.16 11.40 ± 1.33 3.76 ± 1.18

WC11A 7.48 ± 0.66 89.09 ± 6.70 0.98 ± 0.12 42.81 ± 4.10 0.38 ± 0.16 9.19 ± 1.06 3.77 ± 0.92

WC11B 7.04 ± 0.62 105.89 ± 7.86 0.81 ± 0.18 44.18 ± 4.55 0.33 ± 0.11 9.31 ± 0.79 3.75 ± 0.86

WC11C 5.09 ± 0.63 100.25 ± 6.54 0.88 ± 0.18 40.61 ± 3.89 0.52 ± 0.14 9.70 ± 0.80 3.33 ± 0.74

WC12A 4.81 ± 0.43 92.25 ± 7.44 1.07 ± 0.13 37.23 ± 5.26 0.57 ± 0.18 10.70 ± 0.88 3.31 ± 0.80

WC12B 4.46 ± 0.39 90.99 ± 6.17 0.93 ± 0.12 27.93 ± 2.63 LOD 8.89 ± 0.72 3.39 ± 0.74

WC12C 5.74 ± 0.51 68.78 ± 4.90 0.76 ± 0.18 32.25 ± 3.09 0.31 ± 0.11 8.43 ± 0.73 2.64 ± 0.63

WC13A 7.49 ± 1.47 89.24 ± 6.30 1.12 ± 0.11 42.14 ± 4.39 0.57 ± 0.12 11.71 ± 0.89 3.07 ± 0.84

WC13B 6.80 ± 1.43 107.00 ± 8.25 1.30 ± 0.13 40.37 ± 4.42 0.48 ± 0.10 13.23 ± 1.18 3.71 ± 0.72

WC13C 4.72 ± 1.01 52.37 ± 3.61 0.68 ± 0.08 28.63 ± 3.20 0.48 ± 0.08 5.92 ± 0.48 3.91 ± 0.83

WC14A 8.84 ± 0.72 152.60 ± 9.52 0.83 ± 0.07 52.60 ± 5.22 0.90 ± 0.23 8.99 ± 0.72 13.16 ± 2.07

WC14C 2.87 ± 0.26 47.86 ± 4.30 0.61 ± 0.09 18.11 ± 1.86 0.30 ± 0.05 5.38 ± 0.43 2.74 ± 0.53

WC15A 5.77 ± 1.31 69.57 ± 5.38 0.93 ± 0.11 28.49 ± 2.79 1.24 ± 0.24 7.45 ± 0.61 2.85 ± 0.58

WC15B 6.30 ± 1.08 73.83 ± 5.54 1.05 ± 0.11 35.54 ± 3.67 0.40 ± 0.09 11.69 ± 0.99 2.46 ± 0.54

WC15C 4.01 ± 0.96 55.86 ± 4.16 0.92 ± 0.07 25.05 ± 2.65 0.36 ± 0.07 6.89 ± 0.55 1.74 ± 0.37

WC16A 6.32 ± 1.24 65.34 ± 4.34 1.06 ± 0.10 38.41 ± 3.91 0.31 ± 0.07 10.73 ± 0.70 2.50 ± 0.56

WC16B 6.46 ± 0.66 95.64 ± 7.83 1.19 ± 0.11 40.23 ± 4.27 0.48 ± 0.08 12.24 ± 1.06 3.06 ± 0.75

WC16C 8.51 ± 0.65 113.61 ± 6.68 1.45 ± 0.13 48.28 ± 4.04 0.54 ± 0.08 15.53 ± 0.94 3.77 ± 0.62

WC17A 6.21 ± 0.55 88.95 ± 5.92 1.14 ± 0.10 37.63 ± 3.62 0.44 ± 0.07 12.40 ± 0.97 3.95 ± 0.67

WC17B 107.95 ± 7.54 1.7.43 ± 0.16 68 ± 0.17 52.25 ± 8.88 0.43 ± 0.24 14.47 ± 1.11 3.66 ± 0.74

WC17C 52 ± 0.13 49.23 ± 4.69 0.45 ± 0.21 14.29 ±1.23 3.85 ± 0.72 7.25 ± 0.64 103.56 ± 6.27 1.

WC18A 6.68 ± 0.15 72.81 ± 5.71 1.01 ± 0.12 30.02 ± 3.79 0.27 ± 0.12 10.34 ± 0.79 3.83 ± 0.78

WC18B 5.85 ± 0.16 83.11 ± 6.13 1.08 ± 0.14 38.69 ± 6.26 0.43 ± 0.17 11.17 ± 0.89 4.24 ± 1.15

WC18C 4.05 ± 0.12 61.21 ± 4.05 0.74 ± 0.09 28.09 ± 2.80 0.26 ± 0.11 7.07 ± 0.57 1.98 ± 0.64

Mean 6.40 86.10 1.04 45.54 0.49 10.15 4.06

Max. 8.84 ± 0.72 152.60 ± 9.52 1.68 ± 0.17 103.45 ± 9.67 1.29 ± 0.42 15.53 ± 0.94 13.16 ± 2.07

Min. 2.87 ± 0.26 47.86 ± 4.30 0.61 ± 0.09 18.11 ± 1.86 0.08 ± 0.03 5.38 ± 0.43 1.74 ± 0.37


Table 7 Comparisothose of Strait of Johor an

n of elemental concentration ranges in grab sediments of Strait of Melaka with d with those in average shale, mean crustal material and guideline of

sediment quality of Canadian and Netherlands[11,12,13,14,15] Strait of Johor Strait of Melaka Average Shales Mean Crustal Materials Sediment GL Element Range Average Range Average B, M&M or T&W M&M B Canadian Netherlands Al 3.03-12.19 8.25 ± 2.49 3.84-12.90 7.94 8.0-8.8 8.13 8.20 Ag 0.10-1.00 0.36 0.07 As 6.40-64.0 19.7 ± 6.90 2.72-21.87 8.63 13 1.8 1.50 - 29 Ba - - 33.0-128 61.98 - 425 Br 37.55-319 120.58 2.5 Ca 0.22-15 2.36 3.63 Cd 0.11-0.36 0.18 ± 0.06 0.02-.47 0.17 0.30 0.20 0.11 0.7 0.8 Ce 34.80-97.20 69.3 ± 17.30 47.86-152 86.10 50-96 60 68 Co 1.80-8.10 5.80 ± 1.50 4.64-12.88 8.47 19 25 20 Cr 21.9-62.8 45.20 ± 11.2 29.39-86.49 54.43 90 100 100 52.3 - Cs - - 4.94-14.94 9.63 - 3.0 - Cu 10.8-92.9 30.7 ± 22.5 7.80-21.40 13.36 45 55 50 - 36 Eu 0.49-1.20 0.79 ± 0.20 0.61-1.68 1.04 1.0-1.20 1.2 2.1 Fe 1.53-4.13 3.04 ± 0.67 1.32-4.43 2.72 4.7-4.8 5.0 4.10 Hf - - 4.56-26.91 8.06 3.0 K - - 0.79-1.93 1.45 2.59 La 13.3-65.1 32.1 ± 9.9 18.11-103 45.54 24-92 30 32 Lu 0.25-0.47 0.40 ± 0.07 0.08-1.29 0.49 0.6-0.8 0.5 0.51 Mg - - 0.65-3.13 1.78 2.09 Mn 113-861 265 ±152 148-1013 350 850 950 950 Mo - - 0.30-3.00 1.09 1.50 Na - - 1.01-3.79 2.31 2.83 Ni 21.2-46.8 30.2 ± 6.6 10.0-40.5 26.79 68 75 80 Pb 26.4-69.9 42.3 ± 11.0 20.6-64.77 41.75 20 13 14 30.2 85 Rb 68.8-177 111 90 Sb 0.73-2.73 1.56 ± 0.55 0.41-3.99 1.07 1.5 0.2 0.2 Sc 3.0-13.7 9.9 ± 2.8 5.38-15.53 10.15 13 22 16 Sm 2.1-16.6 7.4 ± 3.4 2.87-8.84 6.40 6.2 6.0 7.9 Sr - - 10.2-378.5 64.43 375 Ta - - 0.95-5.96 1.61 2.0 Th 7.5-64.3 21.2 ± 6.6 12.26-37.38 22.49 12 7.2 12 Ti 0.25-.53 0.40 ± 0.07 0.23-1.11 0.35 0.46 0.44 0.56 U 2.4-7.3 5.2 ± 1.3 2.73-17.09 6.45 3.7 1.8 2.4 V 29.2-118.9 72.5 ± 22.5 32.58-115.0 62.22 130 135 160 Yb 1.3-401 2.7 ± 0.7 1.74-13.16 4.06 2.4 3.4 3.3 Zn 68.5-230.7 132.5 ± 52.6 32.04-119.17 72.98 95 70 75 124 140 B= Bowen (1979); M&M = Mason and Moore (1982); T&W = Turekian and Wedepohl(1961).

References 1. Fukue, M., Nakamura, T., Kato, Y., Yamasaki, S. (1999) “Degree of Pollution for Marine Sediments”

Engineering Geology. 53. 131-137. 2. Fukue, T., Kato, Y., Nakamura, T., Yamasaki, S. (1995) “Heavy Metals Concentration in Bay

Sediments of Japan” STP. 1293. ASTM. 58-73. 3. Morillo, J., Usero, J., Gracia, I. (2004) “Heavy Metal Distribution in Marine sediments fro the

uthwest Coast of Spain” Chemoshere. 55. 431-442. 4. Szefer, P., Szefer, K., Glasby, GP., Pempkowiak, J., Kaliszan, R. (1996) “Heavy Metal Pollution in

Surficial sediments from the southen Baltic Sea off poland” J. Environ Sci Health. A. 31. 2723-2754. 5. Thia-Eng., C., Ross, S., Yu, H. (1997) “Malacca Straits Environmental Profile”. Published by the

GEF/UNDP/IMO Regional programme for Prevention and Management of Marine Pollution in the East Asian Seas. Quezon City, Philippine.

6. Agusa, T., Kunito, T., Yasunaga, G., Iwata, H., Subramanian, A., Ismail, A., Tanabe, S (2005) “ Concentrations of trace elements in marine fish and its risk assessment in Malaysia” Marine Pollution Bulletin. Article in Press.

7. Ahmed, H. (1997) “The Straits of Malacca: International Co-Operation in Trade, Funding and Navigational Safety”, Academe Art & Printing Services Sdn. Bhd.

8. Din, Z. (1992) “Use of Aluminum to normalize heavy-Metal Data from Estuarine and Coastal Sediments of Straits of Melaka. Marine Pollution Bulletin 24, 484-491.

9. Yuan, C., Shi, J., He, B., Liu, J., Liang, L., and Jiang, G. (2004) “Speciation of Heavy Metals in Marine Sediments from the East China Sea by ICP-MS with Sequential Extraction” Environmental International. 30. 769-783.

10. Bokhari,A., Kassim, M. S.(2005) “Operation and Maintenance of 1MW PUSATI TRIGA Reactor” The 2004 Workshop on the Utilization of Research Reactors. Bangkok, Thailand, 17-21 January 205.

11. Wood, A. K. H., Ahmed, Z., Shazili, N. A. MD., Yaakob, R., and Carpenter, R. (1997) “ Strait between Malaysia and Singapore” Continental Shelf

12. Bowen, H.J. M. (1979) “Environmental Chemistry of Elements”, London, Academic Press. 13. istry”, 4th ed., New York, J. Wiley and

14. f the

15. International Atom e tal Neutron Activa rne Partic a.

So

Geochemistry of sediments in Johor esearch. 17. 10. 1207-1228. R

Mason, B.J., and Moore, C. B. (1982) “Principles of Geochemons. S

Turekian, K. K., and Wedepohl, K. H. (1961) “Distribution of the Elements in Some Units oEarth’s Crust”. Bulletin of the Geological Society of America. 72. 175-192.

ic Energy Agency (1992) “Sampling and Analytical Methodologies for Instrum n tion Analysis of Airbo ulate Matter”.IAEA-TCS-4. Vienn

CHARACTERIZATION OF TWO DIFFERENT LIQUID SCINTILLATION COUNTERS:

Noraishah Othman

EFFECTS ON AGE DETERMINATION IN RADIOCARBON DATING SYSTEM

, Kamisah Alias, Nasasni Nasrul, Azwah Jaafar

Tracer Application Group (TAG) Industrial Division (BTI)

Institute For echnology Research (MINT) Bangi, 4300 Selangor, Malaysia

Email: int.gov.my

TechnologyTMalaysian Nuclear

0 Kajang,noraishah@m

bstract A

Age estimation of the radiocarbon samples like geological, hydrological, environmental and rchaeological samples are conducted by using simple program written in Visual Basic, which we

ifferent sections of samples, which are standard f reference samples, radiocarbon samples and background. The current model available is having w background, which is a good counter for age estimation. Due to the mechanical failure, we

RB Model 2700TR fo nts which produces higher background as counter. In this paper f the two different counters were

ed and the effects to the age calculation were determined. The later counter was ed and i d capable to pr result as reliable as the former counter after some ns are do the calculated counts.

: Characte n, Liquid Scintillation Counters, Radiocarbon Dating

enentuan umur sesuatu ten n C-14. ang diperoleh asuk embilang Sintilasi ntuk mene g al dalam sampel tersebut. Model

yang di uid Scintillatio A r Series TRI-CARB Model punyai bacaan background yang rendah dan amat sesuai

untuk pe umur sesuatu osa ng dialami telah mendorong usaha untuk bertukar kepada Pembilang Sintilasi Cecair TRI-CARB Model 2700TR yang

tetapi memberikan bacaan back g tin ertas kerja ini menunjukkan

a mampu pengiraa unt entuan umur sampel setelah eberapa rumusan dilakukan.

atakunci: Pencirian, Pembilang Sintilasi Cecair, Tentumur Radiokarbon.

ntroduction

aadopt from UCD Radiocarbon Laboratory, Dublin. Initially, the radioactivity counts were derived from Liquid Scintillation Analyzer Series TRI-CARB Model 2770TR/SL. The counted activities were then keyed into the program after calculating three doloswitched to TRI-CAcompared to the previous

r radioactivity couthe properties o

characterizcrosscheck s foun oduce modificatio ne to

Keywords rizatio Abstrak

P sampel dibuat menggunakan teknik

i daripada teknik ini akan dimfan

tumur radiokarbokan ke dalam PBenzin y

Cecair u ntukan nilai keaktilah Liq

yang masih tinn

gpembilang2770TR/SL. Model ini m

gunakan iaem

nalyze

digunakan nentuan sampel. Ker kan ya

sedia ada ground yan ggi. Kpencirian yang dibuat ke atas kedua-dua pemkedua jug

bilang ini dan mn yang baik

embuktikan bahawa pembilang uk pen bagi tujuan

b

K I The availability of Liquid Scintillation Counter, LSC, TRI-CARB Model 2770TR/SL in MINT is used extensively for counting C-14 radioactivity in radiocarbon dating system. The results of sample, standard and background counts obtained are keyed in simple age calculation program written in Visual Basic for Percent Modern Carbon (pMC) determination. One major problem occurred when

this LSC broke down; the pMC of the samples cannot be determined and all the subsequent processes delayed. Thus, the presence of LSC TRI-CARB Model 2700TR is fully utilized for the substitution. The practice has not been done before, but some characterizations and similarities on these two ounters have been conducted as to predetermine the reliability and possibility of them if only any of

ot perform well. Moreover, the objective of any counting procedure is to etermine the radioactive content of the sample in question. Whenever a sample is made and counted,

ear decay. Thus, in order to know the absolute value, the ample’s net cpm value should always be converted to (dpm), which requires the knowledge of the ounting efficiency appropriate for each sample. The relationship between cpm and dpm is given

Countinthe char rm of disintegrations per minute (dpm), it’sMerit (F values. Experimental

Benzene recovery The sam l ll the hells that wer ill undergo ne reco and Pola 98, Coo

heat ample Combustion: O2 CO2 (2)

HCl Sample Hydrolysis: Carbonates CO2 (3) Carbide Hydrolysis: LiC2 + 2H2 2H2 + 2LiOH (4) Trimerisation (benzene recovery) 3C2H2 C6H6 (exothermic) (5) The catalyst to complete the polymerization process is chromium activated silica alumina catalyst. Then, the benzene yield is counted using the two different counters for determination of carbon-14 radioactivity.

cthese counters canndthe counter determines the count rate in term of count per minute (cpm) that is a relative value. This is the number of light flashes, which have been seen by the detector, and must be related to disintegrations per minute, which is a nuclscbelow:

dpm = cpm / (counting efficiency) (1)

g efficiency is obtained from the graph of the tSIE vs efficiency correlation curve. Therefore, acterizations have been conducted to the counters in te

efficiency, which is the correlation with tSIE values, sensitivity of the instrument in Figure of OM), radioactivity units and also the difference in pMC

ples obtained are denoted as Arabic numbering from sample one to samp e number five. Asamples are from environmental and experimental samples, that are terrestrial snail se found from different areas in Malaysia namely, Kedah and calcium carbonate. The samples w

three major stages, namely carbon dioxide recovery, acetylene recovery and benze(very respectively. Noakes et al. 1965, Tamers et al. 1974, Belluomini et al. 1978, Gupta

ch 1985, McCormac et al. 1993, Enerson et al. 1998, Muraki et al. 1998, Pawlyta et al. 1902) k 20

S + C

O C

CASA

LSC In many analytical laboratories, ) has become an indispensable technique for the analysis of conventional radiocarbon dating samples [K.G Sushi, H. Polach (1985)]. In the liquid scintillation counting technique the scintillation solvent is benzene (C6H6) because of its excellent light tra of sample C to benzene. In this experiment, each sample is experiencing 500 minutes counts for 10 cycles to obtain the stability of cpm counted. In each cassette, the background, standard and samples are placed in a series

purposes. sing an external standard quench is chosen for this research. The purpose is to provide a

oactive

by

TRI-CARB Model 2700TR are eing discussed in a form of table which encompass gross and net cpm, disintegrations per minute pm), efficiency, which is the correlation with tSIE values, sensitivity of the instrument in Figure of

ioactivity units and also the difference in pMC values.

round.

Counting

Liquid Scintillation Counter (LSC

nsmission properties and the high chemical conversion yield

for data recording Method umeans of determining counting efficiency of any homogenous sample, independent of its radicontent. This method was devised to overcome problems such as the so-called ‘Wall effect’ present insome of the external standard method. Recently, the study of the efficiency and background variationrelated to liquid scintillation counter measurement sites were extensively discussed and reviewedF. Bella et al. Results and Discussions Characterizations of LSC TRI-CARB Model 2770TR/SL and LSCb(dMerit (FOM), rad

Calculation of gross cpm and net cpm (cpmcorrected) Gross cpm is counted from the average value of the total cpm. In this case, the total cpm is being divided into 10, the number of cycles per sample run, whereas corrected cpm is the difference between cpm of samples to cpm of backg

cpm Corrected = cpm samples – cpm background (6)

Type of sample

Gross cpm cpm Corrected

Samples Model 2770TR/SL

Model 2700TR Model Model 2770TR/SL 2700TR

Sample 1 Terrestrial

snail shell 9.4025 23.096 7.88 9.71

Sample 2 Terrestrial snail shell

3.6475 17.79 2.14 4.401

Sample 3 Terrestrial snail shell

7.09 24.183 5.52 10.794

Sample 4 Calcium 1.666 21.403 4.98 8.014 carbonate

Sample 5 Oxalic Acid 32.9125 54.742 31.36 41.426 Table 1. Gross cpm and net cpm of every sample for 500 minutes x 10 cycles

Qu e

counting, the terms quenching and counting efficiency are synonymous. Que

r Model 2700TR. The typical tSIE uench correction curves are shown in Figure 1.

ench Curv In liquid scintillation

nching refers to any factor, which results in the loss of photon emission from the samples, which include chemical agents that reduce the transfer efficiency of the beta energy by the solvent and colored agents, which absorb, within the sample results in a loss of counting efficiency. The level of quench is determined by tSIE for Model 2770TR/SL and SIS foq

tSIE vs efficiency

100

120

80

0

20

40

60

0 200 400 600 800 1000 1200

tSIE

effic

ienc

y

Figure 1. tSIE curves for carbon –14 Disintegrations per minute, dpm = cpm / (counting efficiency) Equation (1) is applied to obtain dpm from the value of net cpm for each sample. Interpolation is conducted to the quench curve for estimation of counting efficiency for each sample.

Counting efficiency Disintegrations per minute (dpm)

2770TR/SL Model 2770TR/SL

Model 2700TR

Samples Model Model 2700TR

Sample 1 92.74 95.41 8.50 10.17 S .84 95.38 2.31 4.6ample 2 92 1 Sa 2 5.99 11.3mple 3 92.2 95.49 0 Sa 92.00 96.09 4.58 8.34 mple 4Sam 5 92.31 95.04 33.97 43.59 ple Table 2. Disintegrations p inute (dpm) counted from efficiency.

igure of Merit (FOM)

O g

M = (Efficiency)

er m correlation of cpm and counting

F F M is defined as a measurement of instrument’s sensitivity based on instrument’s countinefficiency for Carbon-14 and its background. FO 2 ( 7 )

Background

The FOM values recorded for LSC Model 2770TR/SL and Model 2700TR are 7865.35 and 494.20 for

e range of 1 to 156keV respectively. The details are as follow: th

Parameters Model 2770TR/SL Model 2700TR

Background 2.19 cpm 12.53cpm Efficiency 95.85% 95.93% FOM 7865.35 494.20 Tab 3. Fig of Merit va rent coun

Ra ioac y Units The term d s commonly used to quantify the absolu radi ctive content of a radiolabel samples. Ho ver, of radioac of the I a al S em n I) is t cquerel, Bq, which is equivalent to one per second.

Units )

le ure lues for diffe ters

d tivit

pm, i te oawe a unit tivity in term

disintegrationntern tion yst of U it (S he ba

Radioactivity (Bq Sa es/S d Model 2 Model 270

mpl tandar 770TR/SL 0TR

Sa 0.14 0.17 mple 1 Sample 2 0.04 0.08 Sample 3 0.10 0.19 Sample 4 0.08 0.14 Sample 5 0.57 0.73 Table 4. Radioactivity Units in Bacquerel (Bq) Percent modern carbon (pMC)

Absolute Percent Modern Carbon (pMC)

Estimated Error Samples

Model 2770TR/SL Model 2700TR Sample 1 30.58 ± 0.5

29.46 ± 0.25 3.8 %

Sample 2 30.9 ± 1 31.03

± 0.59 4.0%

Sample 3 32.75 ± 0.63 34.06 ± 0.3 3.8%

Sample 4 26.65 ± 0.34 27.91 ± 0.31 4.5% Table 5. Absolute percent modern carbon values for different counters

Conclusions Both counters Model 2770TR/SL and Model 2700TR are reliable to be used in radiocarbon dating system calculation particularly in determining the radioactivity of carbon-14. They represent likeable results for pMC and radioactivity values for which the differences are not prominent. Nevertheless, LSC Model 2770TR/SL is more sensitive due to its low background values. Moreover, the simple program written in Visual Basic is used to determine the radiocarbon content residue in the samples

by pMC calculation and the radioactivity calculation for radioactivity estimation respectively. It is lso found that the amount of residual C14 activity from the counters will not determine the

radioactivity of the C14 in the sample. Acknowledgement The author would like to thank En Ramzah Mohamed from the Instrumentation Group for his assistance in the counter operations and all the colleagues from Radiocarbon Dating Laboratory (RDL) in making this paper a worthwhile. References

1. Liquid Scintillation Analyzer, Reference Manual. Publication No.169-4142. Rev C 2. Liquid Scintillation Analyzer, Manual Reorder No. 1694141. Publication No. 169-4141 Rev.

C 3. Mc Cormac, F.G., 1992, Liquid scintillation counter characterization, optimization and

rbon, 34, 1, 37-45 4. beta-

uan Ujang, Radiocarbon Dating Development and Practices at MINT, Seminar R& D MINT 2002, 25 – 27 June 2002.

6. Radiocarbon Age Calculation Program, www.ucd.ie\c14

a

benzene purity correction, Radioca

Kojola, H., Polach, et al, 1984, High resolution low-level liquid scintillation spectrometer, Int. J. Appl. Rad. Isot., 35, 949-952,207

5. Kamisah Hj Alias, Bashillah Baharudin, Juhari Muhd Yusof, Ahmad Rad

7. K.G Sushi, H. Polach., Radiocarbon Dating Practices at ANU, Radiocarbon Laboratory

Research School of Pacific Studies (1985). 8. Noraishah Othman, Kamisah Alias, Norinsan Kamil Othman, Trimerisation of Chromium

Activated Silica Alumina (CASA) in Radiocarbon Dating System, The 17TH Symposium of Chemical Engineering 2003, 29-30 December 2003.

9. Kamisah Hj Alias, Bashillah Baharudin Juhari, Muhd Yusof, Wan abdul Aziz Wan Muhammad, MINT Radiocarbon Dating Facilities, Seminar R& D MINNT 2000, 17 – 19 Oktober 2000.

10. Kamisah Hj Alias, Noraishah Othman, Zainudin Othman, M.J.Head, Radiocarbon Dating Development At MINT, N.Z.

11. Rozanski K, Stichler W. et al, The IAEA Intercomparison Exercise 1990.

CLASSIFICATION OF CHILLI SAUCES : MULTIVARIATE PATTERN ED GCMS RETENTION TIME PEAKS OF

Email: [email protected]

RECOGNITION USING SELECTCHILLI SAUCE SAMPLES

Low Kah Hina, Sharifuddin M. Zaina, Mohd. Radzi Abasa, Mustafa Ali Mohd.b

aDepartment of Chemistry, Faculty of Science, bShimadzu-UMMC Centre for Xenobiotics Studies, University of Malaya Medical Centre,

University Malaya, 50603, Kuala Lumpur, Malaysia

/ Tel: 603-79674202 / Fax: 603-79674193

Abst

f

chili component

namely general sauces, hot sauces, sauces ith benzoic acid and sauces with garlic. It was concluded that by using chosen retention peaks in the chromatograms of

various sauce samples as multivariate features, CA and PCA can be successfully used to reveal the natural clusters existing in chili sauces according to their organic composition. Keywords: Chemometrics; Chili sauce; Principal component analysis; PCA; Cluster analysis 1. Introduction

Originally, chilli sauces were produced at home. Today, this practice still preservere but most chilli sauces available nowadays are mass manufactured in factories. Today, much effort is spent to ensure that mass manufactured sauces resemble as close as possible home made ones. Some brands do this better than others.

The ingredients used in chili sauces are very similar to those used in tomato ketchup. However, the methods of preparation and the amount of the ingredients used may vary considerably. The primary ingredients in chili sauce are red tomatoes and chilies. The usual sweetener is sugar (sucrose). The proportions of the various spice ingredients are not standardized between manufacturers [1].

Humans are very good at perceiving similarities and differences between objects of different shapes. The goal of pattern recognition in analytical chemistry is finding similarities and differences between chemical samples based on measurements made on the sample [2]. Therefore, pattern recognition appears to be a useful tool to authenticate foodstuffs according to their quality/variety/brand, when a set of samples whose classification is known a priori is available. This study initially involve data collection via instrumental analysis, basically GC/MS. By using only chromatographic techniques, we able to separate the chemical compounds in the sauces, which are mainly capsaicinoid compounds, the pungent principle of capsicum fruits, benzoic acid which is a preservative, and other compounds due to the ingredients of the sauce.

Capsaicinoid compounds are a group of pungent compounds found mostly in capsicum fruits - the main components are acid amides of vanillylamine and C9 – C11 branched-chain fatty acids. There are five naturally occurring capsaicinoids, which have been reported, namely capsaicin, nordihydrocapsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin. Of these, capsaicin and dihydrocapsaicin are the major compounds of most capsicum species. Therefore these compounds have been considered as major indicators of chili product quality [3].

Techniques using GC/MS provide accurate and efficient analysis of content and type of capsaicinoids present in a chili sauce sample. These results are probably the major factors in determining the qualities/variety/brand of those sauces, and are the most important parameters which are used in this statistical

mometric methods been employed in the exploration; this primarily lve t A) and principal component analysis (PCA). Cluster analysis, which

variables (Loadings matrix, L n × m) [4]. PCA enables one to study data structure in reduced dimensions.

ract As a preliminary work on the possibility of separating classes of chili sauces based on taste or customer preferences, organic compounds from different kinds of chili sauces of various brands were separated and analyzed by gaschromatography/mass spectrometry (GC/MS). It was found that these organic compounds do form a basis for separation odifferent types of sauces. The similarity and dissimilarity of chromatograms due to the organic composition of the sauces were explored by multivariate pattern recognition techniques based on cluster analysis (CA) and principal nalysis (PCA). Both CA and PCA results exhibit four linearly separable classes,a

w

study. In this work, different multivariate che

invo he use of cluster analysis (Cinvo the search for natural groupinglves among samples is a preliminary way to study data sets and to discoverthe structure residing in them. PCA is used to transform the original data matrix (X n × m) into a product of two matrices, once which contains information about the objects (Scores matrix, S n × m) and the other about the

2. Experimental

n

hloroform and was later used for a GC/MS analysis with injection volume of 1µL. 2.2 GC/MS analysis

Samples were assayed using a Gas Chromatograph (Shimadzu GC-17A) with a Mass Spectrometer (Shimadzu QP-5000). A 30 m × 0.247 mm × 0.25 µm capillary column, with a stationary phase of (5% - phenyl) – methyl polysiloxane (J & W Scientific, DB-5), was used. For analysis, the initial temperature was 60°C held for 1 min. The temperature was increased from 60 to 280°C at the rate of 10°C/min and held at 280°C for 22 min. The total run time was 38 min. The injection volume was 1.0µL and the total flow of carrier gas was 39.5 mL/min helium. 3. Data processing

Data preprocessing is a very important part of any chemometric data analysis project. It consist of whatever mathematical manipulation of data prior to primary analysis. From the obtained GC profiles, 12 marked peaks were considered as the multivariate variables. They are the compounds eluting at retention times, 7.6 (1), 9.2 (2), 12.2 (3), 17.0 (4), 19.2 (5), 19.5 (6), 21.0 (7), 21.2 (8), 24.4 (9), 25.4 (10), 25.7 (11), and 36.9 (12) minutes. These peaks were examined for their mass spectra and identification of these peaks were attempted. The peaks’ area per weight of sample were preprocessed, then arranged the in an X-matrix (201 x 12). The values of each row represent the measurement of different variable for each sample, and the values of each column represent the measurement of different samples for a particular variable. Each replicate was treated as an individual sample in the data matrix, which then undergo CA and PCA. All these were done by combination of several statistical software packages such a Microsoft® Excel, Teach/Me®-Data Analysis, JMP® and JMP IN®.

2.1 Sample preparation About 1mL of sauce were weighed and extracted with 5mL dichloromethane in a vial for overnight. The

1mL of sauce extracts was drawn and filtered using a 0.4µm nylon filter membrane with a syringe filter into a small glass vial. The obtained filtrate was dried under nitrogen gas, and reconstituted with 200µL of c

Figure 1: Typical GC/MS chromatogram of a chili sauce extract.

Retentiom Time 7.5 9.2 12.2 17.0 19.2 19.5 21.0 21.2 24.4 25.4 25.7 36.9

GCS0036 S01a 782155 0 186056 28568683 12228225 0 5353903 9774055 1426550 10714811 6485459 2731411

GCS0035 S01b 1387435 0 597293 23716034 6519874 0 4026651 10841376 1902577 13662227 8002463 4064320

GCS0035S01c 1613369 0 819216 37251905 11069449 0 6242748 14612206 2076992 19084453 11712994 6083270

GCS0035 S02a 801396 0 386139 18332483 4543486 0 923887 8586443 1914108 10339062 6540138 2461134

GCS0035 S02b 968122 0 385629 14260443 3855149 0 1528811 9105060 1396709 11473199 7115043 2353073

Table 1: Peak areas at particular retention times for a part of sauce samples

In this work, CA was applied to the autoscaled data, the sample were calculated on the basis of Euclidean distances, while Ward hierarchical agglomerative method was used to establish the clusters. Next, PCA was performed on the unscaled data, used to provide data structure in a reduced dimension, retaining the maximum amount of variability present in the data.

4. Results and discussion

4

w resolved. The m/z values obtained om mass spectra of the molecular ions (M ) and fragment ions of selected compounds are shown in Table 2.

.1 Mass spectra analysis

From the total ion chromatograms of chili sauces extracts, compounds eluting at particular retention times ere examined for their mass spectra. Compounds 1, 3, 6 and 8 were not

+fr

Mass/charge, m/z Retention time / Compound Fragment ions

Molecular Ion, M+

1 7.5 unresolved 2 9.2 Benzoic acid 51 65 77 94 105 122

unresolved 4 17.0 Myristic acid 60 73 85 129 185 228

1.0 Linoleic acid 67 81 95 109 123 280

9 195 293 10 25.4 Capsaicin 43 122 137 152 195 305

12

3 12.2

5 19.2 Palmitic acid 60 73 85 129 213 256 6 19.5 unresolved 7 28 21.2 unresolved

24.4 Nordihydrocapsaicin 43 122 137 152

11 25.7 Dihydrocapsaicin 43 122 137 152 195 307 36.9 Vitamin E 43 57 71 165 205 430

Table 2: m/z values of selected compounds.

re 2: ThFigu e capsaicinoids commonly found in chilies.

considered as major indicators of chili product

caps was found

C H

As mentioned before, the pungent capsaicinoids have been

quality. Typical mass spectra of dihydrocapsaicin is shown in Figure 3. The molecular ions (M+) of the aicinoid compounds were confirmed from their mass spectra. The base peak of each compound

to be common at m/z = 137. Other fragment ions had m/z = 43, 122, 152 and 195. A possible empirical formula for fragment ion m/z = 137 from isotopic abundance calculation is

O2. An achievable fragment ion is shown below as:- 8 9

CH2H3CO H3CO

O OH H

m/z = 137

CH2

m/z = 137

The resonance stabilization of this fragment ion suggested its occurrence as the base peak [5].

Figure 3: Mass spectrum of dihydrocapsaicin.

The isotopic abundance calculation of the fragment ion m/z = 195 suggested an empirical formula of C10H13O3N. A possible fragment ion is shown in the decomposition reaction below [6]:-

HO

H3CO

NH

C CH2

O CH2

CHH

R

HO

H3CO

NH

C

OH

CH2

H2C CHR

+m/z = 195

Fragment ions with m/z = 153 and 152 were perhaps due to the ion decomposition reaction below:-

HO

H3CO

NH

C O

HCH R'

HO

H3CO

NH2

C O

HC R'

HO

H3CO

NH2 + R' CH C O

m/z = 153

H

HO

H3CO

NH2

m/z = 152

4.2 Multivariate correlation analysis

From the correlation matrix for GC peaks, peak no. 1 and no. 3 correlate strongly (r = 0.9861); followed by inter-correlation between peaks no. 9, nordihydrocapsai n, no. 10, capsaicin and no. 11, dihydrocapsaicin. Others correlate moderately or weaker. dihydrocapsaicin, capsaicin and dihydrocapsaicin is expected because these ungent capsaicinoids in capsicum fruits. In other word, we can easily conclude that cap ces or natural chili are in a constant ratio. On the other hand, we suspect that the unknown peaks no.1 and no.3 also show similar characteristics as the capsaicinoids, but this nee

4.3 Cluster analysis

CA is a well known technique of data analysis, commonly applied before other mutivariate procedures wing to its unsupervised character, that reveals the natural clusters existing in a data set on the basis of the

ciThe strong correlation between nor

compounds are the major psaicinoids present in chili sau

ds further investigation.

oinformation provided for the measured variables. The results obtained for the case at hand, using the Ward’s method and Euclidean distance are presented as a dendrogram in Figure 4. At distance 700, 3 clusters that can be identified as ‘similar’ were found: from the top, the first cluster is composed of general sauces including a sub-cluster of hot sauces. The second cluster is a group made up of sauces containing benzoic acid as preservative. The last cluster is those sauces with the addition of garlic.

Hot sauces

General sauces

Sauces with benzoic acid

Sauces with garlic

Figure 4: Dendrogram of Cluster analysis. 4.4 Principal component analysis

By performing PCA on the dataset, which was initially preprocessed from GC/MS data of the chili sauces extracts, a series of principal components (PCs) could obtained. Each PC is associated with an eigenvalue. PC1

has the largest eigenvalue and carries the largest variance of the original data, and subsequent PCs carry variance in a decreasing order.

Loadings graph (Figure 5) is used to determine which variables are important for describing the variation in the original data set, and there are no variables with loading close to ±1, revealing that no PC is closely aligned with any peaks. For PC1, peaks no. 1, 2, 3 and 6 do not contribute much to the variance described by PC1. For PC2, it is the other way round; peaks no. 4, 5, 7, 8, 9, 10, 11 and 12 have near zero loading. In addition, peak no. 2 show high negative loading value, which indicates benzoic acid is a meaningful parameter for PC2.

Fig

ult of PCA, Figure 6, shows a plane spanned by first two PCs, representing 95.87 of the ata. There are crowds of points discriminated by PC2 while PC1 primarily determines the

rable classes namely general sauces, hot sauces, sauces with benzoic acid and d from the plot.

ure 5: Loading Plot: PC1 vs. PC2.

The final resariation in the dv

spread of scores. Four major sepasauces with garlic can be observe

Sauces with

benzoic acid

Hot sauce

s

Sauces with garlic

General sauces

Figure 6

t of the sauces.

In this study, the feasibility of using just GC profiles to distiguish between chili sauces variety was

ples in Chillies (Capsaicum Species), Ahmad bin Ab. Wahab, MARDI Res. Bull. 12, 3, 1984, 290-297.

[6] Mc

iller, Statistic and Chemometrics for Analystical Chemistry, Fourth Edition, d, 2000.

Profiling of colour pigments of chili powders of different origin by high-performance liquid chromatography, Agnes Kosa, Tibor Cserhati, Esther Forgacs, Helena Morias, Teresa Mota, A. C. Ramos, Journal of Chromatography A, 916, 2001, 149-154.

[9] Assement of Herbal Medicines by Chemometric – Assited Interpretation of FTIR Spectra, Chew Oon Sim, Mohammed Razak Hamdan, Zhari Ismail, and Mohd. Noor Ahmad, Journal of Analytical Chemica Acta, 2004.

[10] Determination of Benzoic Acid in Chili Sauce by High Performance Liquid Chromatography, J. S. Chia and Z. Badriah, MARDI Res. Bull. 13, 2, 1984, 190-193.

k and iences, Vol. 18, June 2002, 661-665.

Th t Science, Vol. 79, No. 3, 10 August 2000, 287-288

: Score Plot of PC1 vs. PC2. As had been discussed, peaks no. 1, 2, 3 and 6 are the dominant features in PC2. From scores plot, it is demonstrated that those sauces with benzoic acid clusters on the negative area of axis PC2 corresponding to its’ negative loading, while those sauces with garlic are on the positive side. These indicates that the unknown peaks n . 1 and 3 should correspond to the garlic conteno

5. Conclusion

investigated with multivariate chemometric methods. CA and PCA methods have demonstrated similar results; that using certain peaks in the GC profiles as multivariate parameters we are able to reveal the natural clusters existing in the chili sauce samples studied. Acknowledgements The authors gratefully acknowledge Shimadzu-UMMC Centre for Xenobiotics Studies Laboratory for providing he GC/MS instrument and technical support. t

References [1] Grading Manual for Chili Sauce, United State, Department of Agriculture, Agricultural Marketing Service,

Food and Vegetable Division, Processed Product Branch, October 1954. [2] Kenneth R. Beebe, Randy J. Pell, Marry Beth Seasholtz, Chemometrics A Practical Guide, John Wiley &

Son, Inc., New York, 1998. [3] Optimization of High Performance Liquid Chromatographic Parameters for Determination of Capsaicinoid

Compounds Using the Simplex Method, Rachaneewan Karnka, Mongkon Rayanakorn, Surasak Watanesk and Yuthsak Vaneesorn, Analytical Sciences, Vol. 18, June 2002, 661-665.

[4] Characterization of Galician (N.W. Spain) quality brand potatoes: a comparison study of several pattern recognition technique, P. M. Padin, R. M. Pena, S. Garcia, R. Iglesias, S. Barro and Herrero, Analyst, 126, 2001, 97-103.

[5] A Combined Gas Chromatography-Mass Spectrometry (GCMS) study on Pungent Princi

.Laferty, F.W., Interpretation of mass spectra. 3rd ed. Mill Valley, California: University Science Books, 1980.

[7] James N. Miller and Jane C. MEllis Horwood imprint, Englan

[8]

[11] Accelerant classification by gas chromatography/mass spectrometry and multivariate pattern recognition, Beijing Tan, James K. Hardy, Ralph E. Snavely, Analytica Chemica Acta, 422, 2000, 37-46.

[12] Optimization of High Performance Liquid Chromatographic Parameters for Determination of Capsaicinoid Compounds Using the Simplex Method, Rachaneewan Karnka, Mongkon Rayanakorn, Surasak Watanes

Yuthsak Vaneesorn, Analytical Sc13] e hottest chilli variety in India, Curren[

[14] Gas Chromatographic Determination of Capsaicinoids in Green Capsicum Fruits, Anna M. Krajewska and John J. Powers, J. Assoc. of Anal. Chem., Vol. 70, No.5, 1987, 926-928.

[15] Simultaneous Determination of Capsaicin, Dihydrocapsaicin and Nordihydrocapsaicin in Capsicum Fruits by Gas Chromatography, Kazuhiko Sagara, Sadao Kakizawa, Kohji Kasuya, Tetsuo Misaki and Hiroshi Yoshizawa, Chemical and Pharmaceutical Bulletin, 28(9), 1980, 2796-9.

[16] Gas Chromatography Method for Measuring Pungency in Capsicum Spices, John I. Morrison, Chemistry & Industry (London, United Kingdom), 42, 1967, 1785-6.

[17] Simultaneous HPLC determination of carotenoids used as food coloring additives: applicability of accelerated solvent extraction, Dietmar E. Breithaupt, Food Chemistry, 86, 2004, 449-456.

[18] Selective Enzyme-Mediated Extraction of Capsaicinoids and Carotenoids from Chili Guajillo Puya (Capsicum annuum L.) Using Ethanol as Solvent, R. I. SaM. Gama, M. Mota and A. Lopez-Munguia, J. Agric. Food Ch

ntamaria, M. D. Reyes-Duarte, D. Fernando, F. em., 48, 2000, 3063-3067.

] Isocratic non-aqueous reversed-phase high-perform iquid chromatography separation of capsanthin and capsorubin in red peppers (Capsicum annu , I. Schaeffler, E. Menagem, M. Barzilai, A. Levy, Journal of -95.

[19 ance lum L.), paprika and oleoresin, M. Weissenberg

Chromatography A, 757, 1997, 89

CORRELATING STUDENTS’ VIEWS ABOUT CHEMISTRY AND THEIR CONCEPTUAL KNOWLEDGE IN FIRST YEAR CHEMISTRY

Zarila Mohd Shariff & Jaafar Jantan Applied Science Education Research

Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor

Email: [email protected]; [email protected] Phone: 03-5544-4606; 03-5544-4593. Fax: 03-5544-4562 Website: http://www.uitm.edu.my/faculties/fsg/drjj1.html

Abstract: Research have shown that learning and academic achievement for students in chemistry has been associated with not only their perceptions on science but most importantly their existing knowledge, particularly in Chemistry. Samples for this study are the applied science students doing their degrees and diplomas at UiTM Shah Alam and Arau cam ses and the science students at Matriculation Co emistry were determined using the

mistry (translated into Bahasa Melayu by J. Jantan with permission from the author) which was ., at the University of Arizona. The views were categorized into profiles of

we can infer that students, hose views about chemistry match those of the experts, do have a better understanding about basic chemistry.

Keywords: FCI, emical Con ist, n . Introduction Many students leave high school chemistry r c ist ith profo i derst gs about the nature of ma chem rocesses, and ch stems. Due at re is ge growing body of research on misconceptions (or “ rn con ons”) had m ted. To help

culty identify the concepts that their students do not understand or misconceptions that they have, a number

atics, Newton's First, Second, and Third Laws, the superposition principle, and types of forces (such as gravitation, friction). Each question offers only one correct Newtonian solution, with common-sense distractors (incorrect possible answers) that are based upon students’ misconceptions about that topic, gained from interviews. The FCI is now available in nine languages: Chinese, English, Finnish, French, German, Bahasa Melayu, Spanish, Swedish, and Turkish.

Another widely accepted instrument is the mechanical baseline test (MBT) developed by Hestenes, D. and Wells, M. [3]. MBT is an advance companion of the FCI. It contains questions that are designed to probe concepts and principles that cannot be grasped without formal knowledge about mechanics, and require both qualitative and quantitative approach to answer them, which is more involved than just plugging in numbers into formulas. The two tests together assess students’ conceptual understanding of basic Newtonian mechanics that are generally covered in an introductory physics course. The MBT covers concepts in kinematics (linear and curvilinear m tion), basic principles (Newton ergy onservation,

pullege, Arau Campus. The students’ views about ch

Views about Science Survey (VASS) in Che developed by Hestenes et. al

either experts (EP), high transitional (HTP), low transitional (LTP) or folk profiles (FP). We found that only 8.5% out of 483 are the EP (matches that of chemistry lecturers), 31.7% the HTP, 41.6% the LTP and 18.2% the folk profile. Conceptual understanding in basic chemistry were determined using the Chemical Concept Inventory (CCI), a 22-item, multiple choice question, developed by Mulford (1996). The mean score on the CCI is 30.38% with a standard deviation of 12.7%. This score is very low considering that CCI probes only the conceptual understanding. The mean CCI score for each of the VASS profiles are 31.71% for the EP, 33.07% for the HTP, 29.95% for the LTP and 27.94% for the FP. The mean scores between he HTP and the LTP, and the HTP and the FP are shown to be statistically significant. Thus, t

w

Ch cept Inventory, VASS, constructiv chemistry, learni g

o ollege chem ry w und m sun andintter, ical p emical sy to th the a lar

alte ate cepti accu ulafa

of instruments called concept inventories or CI’s had been developed. An oft-cited instrument is the Force Concept Inventory (Hestenes, Wells, and Swackhamer, 1992 [1]; Hake 1998 [2]) which was then revised by Hestenes et. al in 1995. The revised version of FCI has 30 qualitative items, with subscales, dealing only with the Newtonian concept of force and motion. It is extremely effective in eliciting the “commonsense” notions of students about motion as opposed to the scientific beliefs. It is an instrument designed to assess students understanding of the most basic concepts in Newtonian physics. The questions were designed to be meaningful to students without formal training in mechanics. This FCI looks at six dimensions namely kinem

ocs' First, Second, and Third Laws, superposition principle, en

impulse-momentum, and work) and special forces (gravity and friction). The MBT is available in four nguages: English, German, Spanish, and Bahasa Melayu. These CI have been tested for their

time. In fact, some of these alternative conceptions were found to be the result of instructions [8]. Much of the areas of chemistry and th mistry were reviewed by Taber [9]. On the other and, res knowing and lear istry were done by Halloun et.al., [8] (VASS), an instrument developed and validated by the sam

The Chemis y VASS (V s Abo cience Sur ment consisting of 30 items and de probe the personal beliefs abo e na f science and about the learning of science. Beliefs about sc were probed within three scientific dimensions

ertaining to the structure, methodology and validity of science. Beliefs about the learning of science were probed within three cognitive dimensions pertaining to learnability, reflective thinking and personal relevance of science [8].

The aim of this study is to determine the correlation between the students’ views about chemistry and their conceptual knowledge in first year chemistry among applied science students pursuing their degrees and diplomas at UiTM Shah Alam and Arau campuses and the science students at Matriculation College, Arau Campus. We intend to find out if academic background and gender contribute to students’ beliefs about chemistry and chemical concepts. Methodology Perception about chemistry. Students’ perception about chemistry, were probed by using VASS. VASS profiles provide a

mprehensive index of istry. VASS contains 30 ems, 13 pertaining to the scientific dimensions and 17 to the cognitive dimensions. The items are

ula s Design (CAD). Each CAD item requires respondents balance primary view against a contrary view on the eight-point scale [7]. This is shown in Figure

lavalidity and reliability. Prompted by the success of FCI, many CI’s, have been and continues to be developed especially to evaluate identify students’ initial beliefs and students’ understanding in the basics of chemistry such as Chemistry Concept Inventory (ChCI) developed by Pavelich, Michael [4,5], Chemical Concepts Inventory (CCI) developed by Mulford, Douglas R. [6] and California Chemistry Diagnostic Test (CCDT) developed by Russell, A.A. [7].

Achievement in chemistry classes cannot progress very much to most learners as long as their alternative conceptions are not confronted and new knowledge is not constructed in due

e learning difficulties that learners encounter in cheh earch into the ning of chem

through the use of the Views About Science Surveye group.

tr iew ut S vey) is a paper-and pencil instruinten d to ut th ture o

iencep

coit

students’ views about knowing and learning chem

form ted in a novel Contrasting Alternativeto1. Contrasting Alternatives Design is used in the construction of VASS in order to overcome major validity and reliability problems encountered in traditional assessment formats. [8].

Penyelesaian masalah kimia memerlukan saya:

(a) pernah melihat penyelesaian kepada masalah yang sama sebelum ini. (b) boleh menggunakan teknik umum penyelesaian masalah.

1 2 3 4 5 6 7 8

Bukan (a) atau (b)

Kearah “Hanya (a)” Kearah “Hanya (b)”Samarata (a) & (b)

Fig sting Alternative Design e of the V items. ure 1. A contra in on ASS

In this study the Bahasa Melayu version of VASS was used. VASS was translated by one of the auth

onceptual Knowledge in Basic Chemistry Students’ conceptual knowledge in basic chemistry wa iagno sing Chemical Concepts Inventory (CCI) develop a multi hoice i s.

uestions on CCI are no ematical and are based on concepts from several topic areas of first ; conservation of substance, weight and mass;

ica ; macroscopic versus microscopic properties;

In 2004 and early 2005, Chemical Concept Inventory and the Bahasa Melayu Chemistry VASS were administered to 324 UiTM chemistry students at the Faculty of Applied Sciences from the Shah Alam campus and from the Arau campus and also to 159 Matriculation College students. The UiTM subjects are students who are doing their diploma in industrial chemistry and doing degrees in chemistry and applied chemistry, ranging from Year 1 to Year 3. Our intended population is chemistry-based students at colleges and universities but for this work, the sample were chosen based on convenience and the willingness of the lecturers in contact with the students to administer both the CCI and the Chemistry VASS. The students usually spent about an hour to complete the CCI and thirty minutes to complete the survey. Those who could not finish on time were allowed to take the VASS papers home and were requested to send the completed survey to us in due time.

Subjects from the Matriculation College were science students from Arau campus and in their final semester. One of the authors administered the CCI to the students while Chemistry VASS was administered by their lecturers.

Subjects’ personal profile and their responses to both CCI and VASS were keyed-in into preadsheet MS™ Excel. Statistical analysis was performed using both the SPSS (Statistical Program r Social Science) version 12 and MS™ Excel for Windows. Some of the responses were coded for

analysis along the scientific and cognitive dimensions.

Results and Discussion This section offers a broad characterization of college students’ views about knowing and learning chemistry and their relation of these views to students’ conceptual knowledge of basic chemistry. The first part of this section describes the students’ perception of chemistry and how they are classified. I. Items Response Classification Students’ views on individual items were classified into three types, namely the expert, mixed and folk views. An expert answer refers to an answer chosen by teachers or professors in chemistry. Their answers are polarized toward one end of the scale (scale of 1 through 8). Therefore, on some items, these experts overwhelmingly chose the extreme option of 1 or 7. On others, a large majority oncentrated on two or all three options 1 through 3, or 5 through 7. A student is classified to be olding an expert view on a given item if his or her answer falls within the ranges chosen by the xpert. On the contrary, a student is classified as holding a folk view on a given item if he or she

chose a polar opposite to the experts’ options. A student is classified as holding a mixed view on a

ors in the year 2001 with the permission from Hestenes et.al. The instrument was piloted by UiTM chemistry and chemical engineering lecturers to eliminate ambiguities, confusion or weaknesses in the translation and sentence structure. Following suggestions by the experts, changes were made to improve the clarity of the questions.

C

s d sed by ued by Mulford, R. CCI is ple c nstrument that contains 22 item

Qse

n-mathmester college chemistry covering phase changes

chem l symbols, chemical equations and stoichiometrysolutions; and size of atoms. CCI was chosen in this study because the questions in CCI are based on concepts which form the foundation of several topics of beginning chemistry. The subjects

sfo

che

given item if he or she shares the middle position with those of the experts who did not express an xpert view. Example of this is shown in figure 2 below. e

17. Setelah guru menyelesaikan sesuatu masalah yang mana penyelesaian saya adalah salah:

(a) saya buang penyelesaian saya dan

saya belajar penyelesaian yang ditunjukkan oleh guru

(b) saya cuba menentukan perbezaaan penyelesaian

saya dan penyelesaian guru.

Figure 2: Students’ responses on VASS item 17 showing classification of expert, mixed and folk views

Item 17 Responses

0.05.0

10.015.020.025.030.0

1 2 3 4 5 6 7 8

Stud

ent P

erce

ntag

e

Series1

expert folk mixed

Figure 2 shows that 67% of the students responded with the expert view which are options 5 through

; 17% of the students responded with the mixed view which is option 4 and the 14% responded with which is option 1 through 3. For this particular item, a significantly high number of

udents share the views of experts but it is not the intention of this paper to comment or analyze

re p tems.

bee

Pro ems out of 30

7the folk viewstresponses to each and every one of the items. Instead, the focus is to classify students’ profile with

s ect to VASS encompassing all 30 i

II. Profile Classification and Description

Further classification was made to the students’ choice of answers to establish the overall industrial chemistry students profile distribution on the perception of chemistry. Hence, students responses had

n grouped to four types of profiles namely, expert (EP), high transitional (HTP), low transitional (LTP), and folk (FP). Cutoffs for the profiles are shown in Table 1.

Table 1: General Profile Characteristics. file Code Abbreviation Number of It

Expert 1 EP 19 items or more with expert views High Transitional 2 HTP 15 to 18 expert views

w Transitional 3 LTP 11 to 14 items with expert views and at most thLo e same number of items with folk views

Folk 4 FP 10 items or less with expert views

Hence, students scoring more than 19 items corresponding to the expert views, are categorized as experts and those scoring more than 15 items corresponding to the expert views are considered as strong potential to become experts while the others are quite far from sharing views of

re 3, out of 483 matriculation, diploma and degree students, only 8.5% evinced an Expert Profile (EP), 31.7% in the High Transitional Profile (HTP), 41.6% in the Low Transitional Profile (LTP) and 18.2% in the Folk Profile (FP). More than 59% of the subjects in our sample made up the LTP and FP. It is understandable that only a small portion of our sample exhibits the expert view in knowing and learning of chemistry but the large percentage, 42%, of the sample belonging to LTP is quite upsetting. Our finding agrees with the study done by Shariff [10] on Industrial Chemistry students views on the knowing and learning of chemistry.

the experts.

As shown in figu

0.0

10.0

20.0

30.0ent

40.0

50.0

Perc

EP HTP LTP FP

VASS Profile

St nudents Overall Profile Distributio

Figure 3: Overall profile distributions of students.

a. Academic Background In order to better understand the trend, an analysis of the profile according to academic background is done. Table 2 and figure 4 shows the profile distribution of students by academic background. The percentage of Diploma students sharing the experts’ views is the highest at 10.5% compared to only 6.3% for the Matriculation students and 8.9% for the Degree students. Even so, a chi-square analysis revealed that the differences are not significant at the 95% confidence interval.

Table 2: Profile distribution of students based on academic background.

Students Count Students Count Students Count

# % # % # %

EP 10 6.3 EP 14 10.5 EP 17 8.9 HTP 40 25.2 HTP 45 33.8 HTP 68 35.6 LTP 67 42.1 LTP 53 39.8 LTP 81 42.4

Matriculation

FP 42 26.4

Diploma(N=133)

FP 21 15.8

Degree (N=191)

FP 25 13.1

(N=159)

The result shows that more matriculation students belong to the Low Transitional Profile and

lation students only had a maximum of 4 chemistry diploma and degree students, hence more of the

the Folk Profile (68.5%) compared to students who are doing their diploma (55.6%) and degree (55.5%) programs. We believe that students’ knowing and learning of chemistry gets better as they take more chemistry courses. Since the matriculasses as compared to at least 10 courses for the c

matriculation students are in the low transition and folk profiles. Again, a chi-square analysis revealed that the differences are not significant; hence we infer that whether we are dealing with matriculation, diploma or degree students, the trend of the profile is equal.

Students Profile Distribution

0.0

10.0

20.0

30.0

40.0

50.0

EP HTP LTP FP

VASS Profiles

Perc

enta

ge MatriculationDiplomaDegree

Figure 4: Profile distribution of students according to academic background.

b. Gender

ale and female differ in ways that they view chemistry. For this purpose e only looked at the general trend and not analyzing the gender issue for each of the academic

imilar for both the gender. Both, have about the same percentage in the transitional profile (72% - 75%). The difference is the percentage of female (10.5%) sharing the experts profile is higher than that of the male (4.0%), and the female students also have lower percentage belonging to the folk profile (17.2%) compared to the male (20.5%). A further analysis using the chi square method show that the difference is not statistically significant at the 95% confidence limit. In other words, gender is not a factor in the distribution of the profile.

Students Count Students Count

We also looked at how the mwgroup. Generally, the trend is quite s

Table 3: Profile distribution of students according to gender.

# % # %

EP 6 4.0 EP 35 10.5 HTP 50 33.1 HTP 103 31.0 LTP 64 42.4 LTP 137 41.3

(N=151)

Female(N=332)

Male

FP 31 20.5 FP 57 17.2

0.0

10.0

20.0

30.0

40.0

50.0

Perc

ent

Male Female

VASS Profile

Students Profile Distribution

EPHTPLTPFP

Figure 5: Profile distribution of students according to gender

III. Conceptual Knowledge of Chemistry The overall mean score of CCI in our study is 30.38% with a standard deviation of 12.7%. The mean

ncepts is, on the average, equal. The results show that our science or chemistry students’ beliefs and reasoning are not scientific in many of the basic chemistry topics. In other words, these students have not been able to construct and connect the most basic and fundamental chemical concepts even though they have taken and passed or aced the chemistry courses they had taken. If we had placed a cutoff score of 60 as the crossover score [1], then it is obvious that all our subjects failed to qualify as chemical believers. In fact, the mean score is just a bit higher compared to a score of 25 which a student would obtain by random guessing.

Table 4: Means of CCI by academic background

score of chemical concept inventory for various academic backgrounds is shown in Table 4. Our results show no matter at what level a student is regarding their academic level; their understanding of undamental chemical cof

Academic N Mean (%) Degree 191 29.8 Diploma 133 30.5 Matriculation 159 30.9

A t-test comparing the mean score for the male students and female students found the

difference to be significantly different at the 99% confidence limit (t = 5.998, p = 0.000) but the score is still far below the cut-off score. It is as if the students don’t know the answer to each item and are just randomly guessing or in fact responding as what they believe the answer should be, without strong conviction and scientific reasoning to justify their answer. Failing to justify their belief indicate poor knowledge about the topic being assessed.

Table 5: Means of CCI by gender Gender N Mean (%)

Male 151 35.3 Female 332 28.1

IV. Student Views and Academic Achievement

r conceptual knowledge in basic chemistry

Educational researchers speculated that students’ views about knowing and learning science affect their understanding of what they are taught in science courses [9, 10]. In testing this conjecture, we ssessed the relation between VASS profiles and theia

25.026.027.028.029.030.031.032.033.0

nt

34.0

Perc

e

EP HTP LTP FP

VASS Profile

CCI Mean (%) versus VASS Profile

Figure 6: CCI mean score for various VASS profiles

The mean scores for those belonging to the experts and high transitional profiles are significantly higher than those whose views about chemistry belong to the low transitional and folk

VASS measure along both the scientific and cognitive dimensions we ores on CCI and the students’ profile on VASS. In fact, the

al analysis showed a positive correlation at the 99% level. Upon performing ANOVA and t-tests for independent samples, we found that the difference in the CCI scores between the HTP and LTP (t = 2.903, p = 0.004) and the difference between the HTP and FP (t = 2.881, p = 0.004) are statistically significant. The HTP mean score is 33.1%, the mean score for the LTP is

and the mean score for the FP is 27.9%. It’s quite surprising that the EP group mean score to e the same as the HTP group. Nonetheless, we could infer that the knowledge and understanding of

the EP and HTP group are at par but are a bit higher than the LTP and FP group. Still, due to the low scores, the differences we observed do not contribute very much to the advancement of chemical learning. However, being able to categorize the students into the respective profile will help us identify those who will have good grasps of chemistry concepts and hence might lead us to predict those who will excel in chemistry-related courses and career.

profile. Since the Chemistryexpect a strong correlation between scspearman’s-ρ statistic

30.0%b

Conclusion

for students who are taking or have taken any chemistry or chemistry-related courses. If we can adopt interpretation from the FCI, the

worryingly low score reflects shallow understanding which is then related closely to failure of instruction. Instructors failed to identify common-sense beliefs that are at odds with the scientific beliefs that students possess and continue to hold-on to, even after completing few chemistry courses. It seems that those whose science beliefs are matching or on the verge of matching the experts beliefs, their CCI score will be much higher, but not high enough to crossover into the chemical beliefs. Again, instructional strategies play a major role in assuring that students do have the knowledge of basic concepts in chemistry in order for them to generate new scientific knowledge. More research and researchers are required to identify, problems in students learning of chemistry and how to best teach the subject of chemistry. Advancement in the world of chemistry can be achieved in a much shorter period if all who graduates in chemistry do actually understand the chemical concepts and processes in chemistry and are able to contribute immediately in the accumulation of new knowledge. Acknowledgement This work is supported, in part, by the Institute of Research, Development and Consultancy and by the Faculty of Applied Sciences, UiTM, Shah Alam. References 1. Hestenes, D., Wells, M., & Swackhame G. (1992). Force Concept Inventory. The

Physics Teacher, 30, 141-158. 2. Hake, Richard R. (1998). Interactive engagement versus traditional methods: A six-thousand-student survey

of mechanics test data for introductory physics courses. American Journal of Physics, 66 (1), 64-74. 3. Hestenes, D. & Wells, M. (1992). A Mechanics Baseline Test. The Physics Teacher, 30,

159-165. . M. Pavelich, B. Jenkins, J. Birk, R. Bauer, and S. Krause, "Development of a Chemistry

B., and Pavelich, M.J. (2004). "Development, Testing, and Application of a Chemistry Concept Inventory," Proceedings, Frontiers in Education Conference, Savannah, GA, USA

6. Mulford, D.R., and Robinson, W.R. (2002) “An Inventory for Misconceptions in First Semester General Chemistry”, Journal of Chemical Education, pg739 ff.

7. Russell, A.A. (1994). A rationally designed general chemistry diagnostic test. Journal of Chemical Education, 71 (4): 314-317.

8. Halloun, I.,& Hestenes, D. (1998). Interpreting VASS Dimensions and Profiles. Science & Education, 7(6), 553-577.

9. Taber, K.S. (2001). Building the Structural Concepts of Chemistry: Some Considerations from Educational Research, 2(2)

We feel that the mean score for CCI is embarrassingly lowm

r,

4Concept Inventory for Use in Chemistry, Materials, and other Engineering Courses," Proceedings, ASEE Annual Conference, Salt Lake City, UT, June 20-23, 2004.

5. Krause, S., Birk, J.P., Bauer, R.C., Jenkins,

, pp. 123-158. 10. Shariff, Z. & Jantan, J. (2003). Proceedings Symposium Kimia Analisis Malaysia XVI,

Sarawak, Malaysia.

SYNTHESIS AND FLUORESCENCE CHARACTERISTIC OF 2-SUBSTITUTED AND 6-SUBSTITUTED PURINES

Zanariah Abdullah, *Maizatul Akmam A. Bakar, Ernie Iryana Awang Din, Nadiah Rifhan

Abd. Rani, Noordini Mohd Salleh, Goh Poh Leong, Liow Pei Ling and Zaharah Aiyub

Chemical Synthesis Group, Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur

email: [email protected] Abstract. 2-Fluoropurine was prepared from 2–aminopurine through a diazotization reaction, followed by treatment with fluoroboric acid. 2-Aminopurine was obtained from a series of reactions, using 5-nitrouracil as the starting material. 2-Piperidino and 2-anilinopurines were obtained by treating 2-fluoropurine with piperidine and aniline respectively. 6-Piperidino and 6-anilinopurines were obtained by treating 6-chloropurine with piperidine and aniline. Fluorescence studies was carried out in various solvents and maximum fluorescence was observed in 75% ethanol. 2-Aminopurine showed the highest fluorescence intensity, followed by 2-anilino and 2-piperidinopurines. 6-Substituted purines showed stronger fluorescence intensities compared to 2-substituted purines. Abstrak. 2-Fluoropurina disediakan daripada 2-am lalui tindak balas pendiazoan diikuti dengan pengolahan dengan asid fluoroborik. 2-Aminopurina diperolehi melalui beberapa peringkat tindak balas bermula

o dan 6-piperidinopurina pula diperolehi apabila 6-kloropurina ditindak balaskan denga Kajian pendafluoran dilakukan menggunakan berbagai pelarut dan kadar

rine system is one of the most im s pre ystem m can be fo ny natural products clud m and several

compounds which a for trea t of cancer. Ev ough many of s can be found in the natural occur s, the pa ompound itself cannot be found in .

pure purin , was ob d by the isolation from kidneyston 776 [1] but its was conf hundred r later by Medicus [2]. But the of purines

om 1906 onwards [3-5] until today. The purine rimidine or imidazole as the precursor. The most extensively used method is the Traube Sythesis which involved

The fluorescence characteristic of purines or other heterocycles are not extensively studied, eventhough a wide variety of heterocyclic compounds are known to be fluorescent [6]. Fluorescence studies of these compounds are made more difficult because their fluorescence characteristics are often dependent on the solvents used. The aim of this work is to study the fluorescence charateristic of selected alkylaminopurines and the effect of solvent on the fluorescence characteristic. In this paper, only the characteristic of 2- and 6- anilino, 2- and 6-piperidino purines will be discussed.

inopurina me

dengan 5-nitrourasil. 2-Piperino dan 2-anilinopurina diperolehi apabila 2-fluoropurina ditindak balas dengan piperidina dan anilina. 6-Anilin

n piperidina dan anilina. pendafluoran maksima diperolehi dalam 75% etanol. 2-Aminopurina menunjukkan kadar pendafluoran yang tinggi diikuti dengan 2-anilino dan 2-piperidino purina. Purina tertukar ganti di kedudukan 6 menunjukkan kadar pendafluoran yang lebih tinggi berbanding dengan purina tertukar ganti di kedudukan ke 2 yang setara. ntroduction I

The pu portant system

, insent in living s

ucleotides, co-enzys. The purine syste

es or rings und in ma ing nre valuable tmen en th its ring

ring product rent c nature The first e, uric acid taine es in 1structure irmed one yea chemistryflourished fr

ring can be synthesized using two main synthetic route, either using py

the use of diaminopyrimidines, whereby the diaminopyrimidines are condensed with a simple compound to supply a one-carbon fragment to bridge the two pyrimidine amino nitrogen atoms to form a five-membered ring. In this work, the Traube method was used in the synthesis of 2-fluoropurine.

Experimental Synthesis of 2-fluoropurine 2,4-Dichloro-5-nitropyrimidine [7] 5-Nitrouracil (26 g), phosphoryl chloride (130 ml), and dimethylaniline (32 ml) were heated with occasional shaking until the reaction commerced. When this has subsided, the mixture was refluxed for 1.5 hours, cooled and phosphoryl chloride was evaporated off. The residue was poured onto crushed ice with vigorous stirring, and extracted with ether (500 ml). The ether extracts were washed with water and dried over anhydrous sodium sulphate. Removal of ether and vacuum distillation gave

ure product. 89%, IR (cm-1):1670, 1620, 1350, 785; 1H NMR (CDCl3) δ: 9.26, s, 1H, (H6).

, 4-Diamino-5-nitropyrimidine [8]

0%, IR (cm-1): 3345, 1675, 1630, 1350; 1H NMR (CDCl3) δ: 9.15, s, 1H, (H6), 7.20, b, 2H (NH2 of H (NH2 on C2).

ted with ethanol (7.5 ml) to remove odium carbonate. Evaporation of filtrate gave the pure product.

1670, 1625; 1H NMR (DMSO-d6) δ: 7.25 s, 1H (H6), 6.00, b, 4H (NH2 of C2 nd C ), 5.10, b, 2H (NH of C ).

] , 4, 5-Triaminopyrimidine (0.3 g), formyl morpholine (1.2 ml) and formic acid (0.6 ml) was heated

d for one hour in nitrogen atmosphere. Acetone (2 ml) was added to precipitate 2-inopurine which was dissolved in boiling water (3 ml). The solution was passed through a wide

nitric acid and refrigerated. The nitrate was filtered off. The ter and brought to pH 6.8 with sodium citrate and 6N

arcoal, giving buff-coloured crystals of 2-

δ: 8.70, s, 1H (H6), 8.00 s, 1H (H8) 6.25, b, 2H

ater) was added with stirring to a solution ml per minute at -11 oC. en

eutral ith

a soxhlet extractor. Evaporation of ether gave crude product, which was recrystallised from water. 35%, IR (cm-1): 3325, 1673, 1623, 1132; 1H NMR (DMSO-d6) δ: 8.70 s, 1H, (H6), 8.00 s, 1H (H8), 6.50, b, 1H (NH).

p

22, 4-Dichloro-5-nitropyrimidine (10.3 g) and phenol were heated under reflux while a stream of ammonia was passed into the mixture for four hours. The phenol was distilled off and the residual suspension was cooled and filtered. The crystals of 2, 4-diamino-5-nitropyrimidine were washed with water, followed by ethanol and dried. 9C4), 6.50, b, 2 2, 4, 5-Triaminopyrimidine [8] Finely powdered 2, 4-diamino-5-nitropyrimidine (8.9 g) was heated to 80 oC with water (15 ml) and mechanically stirred. Sodium dithionite (3.75 g) was added during 3 - 4 minutes. The resulting solution was stirred until 60 oC, followed by addition of powdered anhydrous sodium carbonate (5.5 g). The thick suspension was taken to dryness in an open basin on water bath. The solid was machine ground and extracted for 20 minutes with stirred boiling alcohol (22 ml) which was filtered while hot. The filtrate was taken to dryness and the product was re-extracs71%; IR (cm-1): 3363, a 4 2 5 2-Aminopurine [92under refluxeamfilter, cooled to 50 oC and diluted with 3N solution was then suspended in boiling wasodium hydroxide solution. The solution was boiled with chaminopurines. Crystallisation with boiling water gave colourless crystals. 40%, IR (cm-1): 3245, 1670, 1620; 1H NMR (D2O)(NH2), 6.50, b, 1H (NH). 2-Fluoropurine (improved method) [10, 11] An aqueous solution of sodium nitrite (800 mg in 4 ml of wof 2-aminopurine (200 mg) in 48% fluoroboric acid ( 22 ml) at the rate of 0.1After the addition was completed, the mixture was stirred for one hour betwe - 10 to 0 oC. The mixture was then neutralized with 50% sodium hydroxide solution. The nslurry was evaporated to dryness. The crude purine was isolated by extraction of dry residue wether in

2Piperidine (20 mg) in ethanol (4 ml) was adde ution of 2-fluoropurine (40 mg) in ethanol (7

l) and the mixture was refluxed for 1 hour at 100 C. The mixture was cooled and ethanol was evaporated off. The washed with water and dried over anhydrous sodium sulphate. Evaporation of ether gave crude product, which was recystallised from petroleum ether. 50%, decomposed above 215, IR (cm-1): 3115, 1673, 1620; 1H NMR δ: 8.70, s, 1H (H6), 8.00, s, 1H (H1), 3.35, m, 4H (H2’, H6’), 1.68, m, 6H (H3’, H4’, H5’); M+: 203.1163.

Piperidine (0.5 ml) in ethanol (3 ml) was added to 6-chloropurine (0.232 g) [11-12] and the mixture

rated. The slurry was extracted with ether, washed with ater and dried over anhydrous sodium sulphate. Evaporation of ether gave light brown solid.

1H (H4’); +: 211.0858.

pectroscopic Analysis All solvents were redistilled before use. Melting points were determined with Electrothermal Melting Point Appararus and were not corrected. Infrared spectra were recorded using Perkin Elmer 298 Infrared Spectrometer and FTIR Perkin Elmer 1600 Series. 1 H NMR spectra were recorded on Bruker WP-80 and Bruker AM 250. Fluorescence studies 2- and 6-Substutitued purines at the same concentration were prepared in various solvents. Quinine sulphate

-Piperidinopurine d to a sol

omslurry was extracted twice with ether. The ethereal layer was

2-Anilinopurine 2-Fluoropurine (80 mg) was added to aniline (3 ml) and warmed at 60 oC for four hours. The mixture was cooled and refrigerated overnight. 2-Anilinopurine was crystallized out of the reaction mixture. The crystal was filtered, washed with ice-cold water and dried. Pure product was obtained after recrystallisation from dichloromethane. 73.5%, decomposed above 200o, IR (cm-1): 3330, 1670, 1630; 1H NMR (DMSO-d6) δ: 8.65, s, 1H (H6), 8.00, s, 1H (H8), 7.20, m, 3H (H3’, H4’, H5’), 6.90, d, 2H (H2’ and H6’), 5.40, d, 2H, (N-H); M+:211.0858. 6-Piperidinopurine

was refluxed for 2 hours. The mixture was cooled and ethanol was evaporated off. The slurry was extracted twice with ether; the ethereal layer was washed with water and dried over anhydrous sodium sulphate. Evaporation of ether gave grey product, which was recystallised from petroleum ether. 30%, decomposed above 270, IR (cm-1): 3115, 1673, 1620; 1H NMR (DMSO-d6) δ: 8.23, s, 1H (H2), 8.15, s, 1H (H8), 2.62, m, 4H (H2’, H6’), 1.66, m, 6H (H3’, H4’, H5’); M+: 203.1163. 6-Anilinopurine 2-Chloropurine (0.161 g) was added to aniline (0.3 ml) in ethanol (3 ml) and refluxed for 3 hours. The mixture was cooled and the solvent was evapow50.3%, decomposed above 280o, IR (cm-1): 3330, 1670, 1630; 1H NMR (DMSO-d6) δ: 9.81, s, 2H (N-H), 8.43, s, 1H (H2), 8.34, s, 1H (H8), 8.01, d, 2H (H2’ and H6’), 7.38, t, 2H (H3’, H5’), 7.08, t, M S

with the same concentration as the compounds under studied were also prepared and used as the standard. The fluorescence intensity of quinine sulphate was taken to be 1.00. The fluorescence measurement was carried out using Fluorescence Spectrometer Model F-2000 Hitachi.

Results and Discussion The synthetic route of 2-fluoropurine is as shown below:-

NH

N

H

O

O

O2NN

N Cl

Cl

O2NN

N NH2

NH2

O2N

2 3

POCl /C H NM

sodium dithionite

3 6 5 e2 Phenol/NH3

1

N

N NH2

NH2

H2N

N

N N

N

HNH2

456

HCOOHN

N N

N

HF

NaNO2/HBF4

Scheme 1

on of 2-fluoropurine was carried out according to the Brown method [4 ], using 5-

itrouracil (1) as the starting material. Purine ring was obtained through cyclisation reaction of 2, 4, 5-idine (4) with formic acid to give 2-aminopurine (5). Compound 5 undergoes

iazotization reaction, followed by treatment with HBF4 to give 2-fluoropurine (6). Low percentage

with aniline and piperidine are as shown in Schemes and 3.

The preparatintriaminopyrimdyield was obtained in the synthesis of 6-chloropurine. Due to low percentage yield obtained, 6-chloropurine used in this work was obtained commercially. Treatment of 2-fluoropurine and 6-chloropurine 2

N

N N

N

HF

NH2 N

N N

HN

NH

N

H N

N N

HN

N

2-anilinopurine

2-piperidinopurine

2-fluoropurine

Scheme 2

N

N N

N

H

Cl

NH2

N N

NH

N N

H

N

HN

N N

H

N

N

6-anilinopurine

substituted purines were confirmed by 1H NMR and mass spectra as given in the experimental se

he fluo of 2- and 6-substituted purines were carried out in 75% ethanol. Quinine

fluoresc

lvent Excitation wavelength/nm

Fluoresence wavelength/nm

Rel. Fluorescence intensity

6-chloropurine

6-piperidinopurine Scheme 3

The structures of 2- and 6-ction.

T rescence studies sulphate at the same concentration as the compounds studied was used as the standard and its

ence intensity was taken to be 1.00. The fluorescence band of 2- and 6-substituted purines were given in Table 1. Purine So

2-fluoro 75% EtOH 350 430 0.640 2-amino 75% EtOH 340 380 0.964 2-anilino 75% EtOH 340 473 0.371 2-piperidino 75% EtOH 340 390 0.307 6-chloro 75% EtOH 330 420 0.650 6-anilino 75% EtOH 340 480 0.452 6-piperidino 75% EtOH 340 395 0.351

Table 1: Fluorescence peaks of 2- and 6- substituted purines in 75% ethanol

It can be seen fro of 6-substituted puri ubstitu t

the two nitrogen atoms as in the 2nd position. As the result, the electrons can move freely

es and fluoresced at a higher wavelength rescence peak observed at a higher wave length is

elieved to be due to the increase in the degree of conjugation in the anilinopurines compared to d with pyrimidine derivatives studied earlier

y was recorded with piperidinopurines in 75% ethanol. This is

m the table that, the fluorescence intensity nes is stronger than 2-

ted derivatives. This is probably due to at the 6- posi ion, the substituent is not sandwich sbetween from the substituent to the rest of the ring. Anilinopurines showed stronger fluorescence intensiticompared to the piperidinopurines. The fluobpiperidinopurines. The same phenomena was observe[13]. Lower fluorescence intensitprobably due to the piperidino ring flipping from one conformation to another, resulted in the loss of energy in the transition state. As the result, low fluorescence was observed.

N

N

N

N

H

NN N

N

N

H

N

N

N

H

N

NN

Flipping of p ring 2- and 6-Pi purines were less rigid c to 2- and 6- . Some energy may lso loss in ition state, which also resulted in low fluoresce observed.

ting nature of the amino group which enhances the e system. The free mobility of the electron enhances the π to π∗ transitions,

onclusion

d purines studied are fluorescent compounds. 2-Aminopurine is the most fluorescent and the fluorescence intensity depending on the type of the substituents. Substituent with high degree of conjugation, as in the case of anilinopurine showed higher fluorescence intensity and fluoresced at a higher wavelength. The purine system with unconjugated substituent (in the case of piperidinopurines) fluoresced at a lower wavelength. Further work on the purine system and other heterocyclic systems are still under going before any concrete conclusion can be made on solvent-structure-fluorescence and substituent-fluorescence relationship. Acknowledgement Financial support of this work by University of Malaya and Academy of Science is gratefully acknowledged. References

. Scheel K. W., Opuscula, (1776), 2, 73. 2. Medius, V. L. (1875), Annalen, 175, 230. 3. Baxter, R. A. and Spring F. S., (1944), Nature, 154, 462. 4. Brown D. J. and Waring P., (1974), J. Chem. Soc. Perkins Trans. II, 204. 5. Tong Y. C., (1975), J. Heterocyclic Chem., 451. 6. Abdullah Z., PhD. Thesis, (1989), Queen Mary & Westfield College, Uni. of London. 7. Whittaker N., (1951), J. Chem Soc., 1565. 8. Brown D. J., Albert, A. and Cheeseman G. (1951), J. Chem Soc., 474. 9. Albe

iperidino

peridino the trans

ompared anilino purince intensity

nesa 2-Aminopurines showed the highest fluorescence intensity amongst all the derivatives of purines tudied. This is probably due to the electron donas

mobility of electron in thwhich resulted in high fluorescence intensity. C All the 2- and 6-substitute

1

rt A. and Brown D. J., (1954), J. Chem Soc., 2060. 10. Montgomery J. A. and Hewson J., (1960), J. Amer. Chem. Soc., 82, 463. 11. Abdullah, Z. and A. Bakar M. A. (2005), sent to Jour. of Organic Chem. 12. Robins R.K., Dille K.J., Willits L.H. and Christensen K., (1975), J.Amer. Chem. Soc., 388. 13. Abdullah, Z., Mohd Tahir N., Abas M. R., Low B. K. and Aiyub Z. (2004), Molecules, 9, 520- 26.

TINDAK BA SASKAN MINYAK KELAPA SAWIT

Zarina Edris*, Norhafipah Mohamad, M. Ambar Yarmo

Jabatan Kimia, Pusat pengajian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia. e-mail: [email protected]

LAS PENGETOKSILAN ASID LAURIK BERA

Abstrak. Dalam kajian ini, surfaktan tidak berion berasaskan tindak balas antara asid laurik (C12) minyak kelapa sawit dengan EO berjaya dilakukan. Sintesis ini menggunakan kaedah pengetoksilan asid laurik dengan siri mol gas etilena oksida iaitu 3,5 dan 7 untuk mengkaji kesan perbezaan di antaranya. Tindak balas ini menggunakan 1% KOH sebagai mangkin dan dilakukan pada suhu di antara 130°C-135°C di dalam reaktor khas. Produk teretoksilat dicirikan menggunakan teknik FTIR dan hasil menunjukkan kehadiran kumpulen ester melalui regangan C=O pada jarak gelombang 1700 cm-1 dan ikatan O-H pada jarak gelombang 2500 – 3450 cm-1. Analisis menggunakan HPLC pula menunjukkan peratus penukaran hasil yang tinggi (>90%). Pengaruh bilangan mol gas etilena oksida terhadap sifat-sifat surfaktan ini dikaji dan didapati bahawa asid lemak teretoksilat (ALT) mempunyai

Abstract. In these studies, nonionic surfactant based on reaction between lauric acid from palm oil derivative with ethylene oxide product was produced successfully. Ethoxylation reaction was carried out between acid lauric with varies moles of ethylene oxide (EO) namely 3, 5 and 7 was investigated effect of different that. The reaction was performance using 1% KOH as a homogenous catalyst performs reaction at temperature between 130°C-135°C. The product was characterization using FTIR technique showed the present of ester group by C=O stretch at wavelength 1700 cm-1 and O-H bond at

500 – 3450 cm-1. HPLC analysis showed a high percent conversion of product (>90%). The effect of oles of EO to surfactant properties are investigated and found that this product have a surfactant

properties that can use as a special detergent.

atakunci: pengetoksilan, asid laurik minyak kelapa sawit, surfaktan tidak berion.

engenalan

egunaan utama bahan-bahan oleokimia selain daripada sektor makanan adalah menghasilkan urfaktan. Sifat ampifilik yang terdapat pada asid lemak boleh diubahsuai dengan mengubah umpulan karboksil kepada kumpulan hidrofilik lain. Keadaan ini boleh menghasilkan pelbagai jenis

surfakta

n minyak kacang soya dan petroleum seperti sulfonat dan sulfat [2]. Penghasilan surfaktan ini banyak digunakan dalam sektor tekstil, farmasi,

pelembap, pengemulsi dan egen pembuih. Dalam industri petroleu gunakan seb mensta inyak me nghid h da ingkiran paraffin [ n surfaktan teretoksilat khususnya s n tidak berion telah ber embang sejak 30 tah mewakili lebih 25% daripada hasil pengeluaran surfaktan dunia. Surfaktan jenis ini tidak menghasilkan ion dalam larutan akues dan berse dengan jenis ag ktif yang lain dalam formulasi kompleks. Ian ang sens hadiran elektro manya ikatan

ivalen kation dan bahagian kaunter ionnya pula menjadikan surfaktan ini sangat berguna dalam larutan air bergaram [2]. Sintesis surfaktan tidak berion boleh dilakukan melalui tindak balas di antara

ciri-ciri surfaktan tidak berion yang boleh digunakan dalam detergen.

2m

K P Ksk

n sama ada anionik, kationik, amfoterik dan tidak berion [1]. Rantai karbon seperti C12-C14 daripada minyak laurik, C22 daripada minyak ikan dan C16-C18 daripada kebanyakkan sumber lain juga boleh digunakan dalam menghasilkan surfaktan. Kebanyakkan surfaktan menggunakan asid lemak dan alkohol lemak yang mempunyai terbitan amida dan amina sebagai bahan pemula [1].

Tindak balas pengetoksilan berasaskan terbitan produk minyak kelapa sawit merupakan alternatif kepada penghasilan surfaktan yang berasaska

detergen, penjagaan diri, kosmetik dan lain-lain sebagai agenm pula, surfaktan

ntah dalam air, pe tidak berion di

rat minyak mentaagai pengemulsi bagi

n menghalang penybilkan m2].

Penggunaaun yang lalu

urfakta k

suaian en tensoaya kur itif terhadap ke lit, teruta

d

etilena oksida (EO) atau propilena oksida dengan kumpulan organik yang mengandungi hidrogen aktif atau kumpulan berfungsi lain dalam kehadiran mangkin bes [1,3]. Tindak balas umum ini ditunjukkan dalam persamaan 1 seperti di bawah [2]

Persamaan 1 X= -O-, -COO-,-CONH-,-NH. R= bahagian rantai panjang organik Surfaktan berasaskan oleokimia seperti minyak kelapa sawit boleh terurai lebih baik daripada petrokimia dan sumbernya juga boleh diperbaharui. Apa yang paling penting, ianya tidak menghasilkan bahan ar seperti NOx, SO2, CO dan hidrokarbon [4 jian ini, proses pengetoksilan dilakukan ke atas asid laurik daripada sumber minyak kelapa sawit. Asid laurik merupakan komponen yang paling banyak terdapat dalam isirong buah sawit. Kelebihan Malaysia sebagai pengeluar utama minyak sawit dunia sehingga tahun 2010 kelak memberikan kemudahan bagi mendapatkan bahan mentah yang lebih murah untuk menghasilkan surfaktan [8]. Fenomena ini sekaligus membuka ruang kepada Malaysia bagi menceburi dan menguasai pasaran surfakatan dunia kelak. Eksperimen Bahan kimia Etilena oksida (EO) (99.8% ketulenan) yang diperolehi dari Fluka. Asid laurik (99% ketulenan) daripada Cognis, kalium hidroksida (85% ketulenan) daripada Aldrich, metanol (99.99% ketulenan) daripada BDH dan Asetonitril bergred HPLC (99.99% ketulenan) daripada Ficher. Air ternyahion (18.2MΩ) digunakan dalam semua penyediaan. Prosedur Tindak balas

besi tahan karat aripada Vinci Technology, Perancis). Reaktor ini dilengkapi dengan sistem pengacau, pemanas aktor dan pengawal suhu. Sebelum tindak balas dilakukan, 1% KOH dalam metanol disediakan

an ada suhu 95°C dalam keadaan vakum selama 1 jam. 100g asid laurik (Cognis) dicampurkan ke alam reaktor dan suhu tindak balas ditingkatkan kepada 135°C. Apabila suhu telah stabil, gas EO

akan disuntik masuk ke dalam sistem reaktor mengikut bilangan mol yang dikehendaki iaitu 3,5 dan 7 ol.

Suhu tindak balas akan meningkat secara mendadak sejurus selepas kemasukkan EO menunjukkan tindak balas ini adalah jenis eksotermik. Tindak balas pengetoksilan dibiarkan berlaku selama 2 jam sebelum suhu reaktor diturunkan kepada suhu bilik. Gas nitrogen dilalukan bagi menyejukkan produk dan menyingkirkan lebihan EO yang mungkin tidak bertindak balas sebelum produk dikeluarkan. Pencirian Produk yang telah dikeluarkan akan dicirikan menggunakan teknik FTIR jenis Perkin Elmer Model GX dan HPLC jenis Agilent Technologies Siri 1100 dengan pengesan ELSD jenis Altech Model 2000. Bagi mendapatkan spektum FTIR, nombor gelombang yang direkodkan adalah dalam julat

O Mangkin bes R-X-H + n H2C CH2 R-X-[CH2-CH2-O]n-H

cem ]. Dalam ka

Tindak balas pengetoksilan dilakukan dalam reaktor 1L yang diperbuat daripada (dresebagai larutan mangkin bes. Kemudian mangkin ini dimasukkan ke dalam reaktor dan dipanaskpd

m

450 cm-1 sehingga 4000 cm-1 dengan resolusi 1 cm-1. Penyediaan untuk analisis FTIR adalah berdasarkan teknik pepejal KBr dan CH2Cl2.

Kromatogram HPLC diperolehi dengan menggunakan turus jenis Zorbax 300SB-C18 (4.6mm x 250mm).Pelarut yang digunakan adalah campuran asetonitril dan air pada nisbah 77:23. Amaun sampel yang disuntik adalah 20 µL dengan kadar alir adalah 1 ml/min.

Keupayaan pembuihan dan kestabilan pembuihan Analisis penentuan pembuihan telah dilakukan terhadap surfaktan tidak berion. Ia biasanya terbahagi kepada penentuan keupayaan pembuihan (foaming power) iaitu kemampuan surfaktan menghasilkan buih dan kestabilan pembuihan (foaming stability) iaitu kemampuan surfaktan mengekalkan tahap pembuihan dalam masa tertentu. Akan tetapi sesuatu surfaktan yang mempunyai kuasa pembuihan yang baik tidak semestinya memberikan kestabilan pembuihan yang baik [5].

Kaedah yang digunakan dalam penentuan pembuihan adalah diperolehi daripada AOTD in-house method. Kaedah ini menggunakan silinder 500ml yang diisi dengan larutan surfaktan (0.2g

gunakan rod

eupayaan Detergen

eupayaan detergen surfaktan yang dihasilkan dilakukan dengan menggunakan fabrik cotton AS9 pigment/oil. Kaedah pencucian ini menggunakan 0.1g surfaktan tidak berion. Kemudian surfaktan

rsebut akan dicairkan dengan 100 ml air suling dan dicampur dengan 50 ppm air liat (hardness ater) selama 3 minit. Selepas proses pencampuran, fabrik cotton AS9 pigment/oil dimasukan ke

dalam bekas untuk pencucian selama 10 minit. Akhir sekali, fabrik cotton AS9 pigment/oil dibilas sebanyak dua kali dengan 1000 ml dan 500 ml air liat (hardness water).

Spektrofotometer CM36000 telah digunakan untuk menentukan peratus penyingkiran kotoran elalui persamaan di bawah:

% penyingkiran kotoran = [(AW-BW)/ (BS-BW)]

dalam 200ml air ternyahion). Larutan surfaktan tersebut akan dikocak dengan mengselama 30 kali pada kadar yang tetap. Selepas pembentukan buih, bacaan akan diambil daripada takat atas dan takat bawah silinder. Bagi keupayaan pembuihan, ia diukur selepas 30 kali kocakan manakala kestabilan pembuihan diukur selepas 5 minit kocakan. Kedua-dua parameter yang digunakan adalah seperti:

Keupayaan pembuihan = [(Takat atas – Takat bawah)/Jumlah ketinggian] Persamaan 2 (selepas 5 minit),

Kestabilan pembuihan = [(Takat atas – Takat bawah)/Jumlah ketinggian] Persamaan 3

K K

tew

m

×100 Persamaan 4

dengan W = selepas cucian terhadap cotton AS9 pigment/oil

m cucian terhadap cotton AS9 pigment/oil BS = sebelum cucian dalam standard clothes

Keseimbangan hidrofilik-lipofilik Keseimbangan hidrofilik-lipofilik menunjukkan hubungan antara hujung hidrofilik dan hujung lipofilik bagi suatu surfaktan. Biasanya, surfaktan yang larut minyak mempunyai nilai keseimbangan hidrofilik-lipofilik yang tinggi. Nilai tersebut juga berkaitan dengan peratus kandungan etilena oksida

ABW = sebelu

dalam surfaktan. Jadual di bawah menunjukkan nilai HLB, kandungan etilena oksida dan penggunaannya. Jadual 1: Nilai HLB , kandungan etilena oksida dan penggunaannya

Nilai HLB Kandungan Etilena Oksida (% berat)

Penggunaan

4 – 6 20 – 30 Pengemulsi air dalam minyak 7 – 15 35 – 75 Agen pembasahan 8 –18 40 – 90 Pengemulsi minyak dalam air

10 – 15 50 – 75 Bahan pencuci 10 – 18 50 – 90 Solubilizer

Nilai keseimbangan hidrofilik-lipofilik bagi molekul surfaktan ditunjukkan dan dikira secara teori

Asid laurik teretoksilat:

melalui persamaan:

HLB = 20 x Berat molekul bahagian hidrofilik / Berat molekul bagi molekul Persamaan 5 Hasil dan Perbincangan

c

b

a

Rajah 1: Profil suhu bagi tindak balas pengetoksilan asid laurik (ALT-3EO).

is surfaktan tidak berion jenis asid laurik teretoksilat (ALT) telah berjaya dihasilkan rsamaan 1. Bahan pemula yang digunakan adalah asid laurik daripada minyak kelapa enggunakan 1% KOH sebagai mangkin. Tindak balas dilakukan dalam reaktor besi

tindak balas dibiarkan selama 2 jam (c) dan didapati terdapat penurunan dan eningkatan suhu pada tindak balas tersebut. Menurut kajian yang pernah dilaporkan, proses

sid lemak berlaku dalam dua peringkat. Peringkat pertama berlaku pembentukan an. Kemudian secara perlahan-lahan tindak balas di antara asid dan etilena oksida

kan be

intesS

berdasarkan Peawit dengan ms

tahan karat pada suhu 135°C. EO disuntik ke dalam reaktor sehingga nisbah molar EO terhadap asid laurik tercapai iaitu 3,5 dan 7 mol.Rajah 1, menunjukkan profil suhu bagi tindak balas eksotermik ALT-3EO. (a) menunjukkan penurunan suhu akibat kemasukkan asid laurik ke dalam reaktor. Kemudian suhu reaktor dinaikkan kepada 130°C -135°C.

Setelah mencapai kestabilan suhu, EO disuntik masuk. (b) menunjukkan sedikit penurunan suhu akibat kemasukkan EO kemudian terus mendadak naik. Pada keadaan ini, tindak balas eksotermik telah bermula kerana berlaku peningkatan suhu melebihi suhu yang ditetapkan (130°C -

35°C). Masa 1ppengetoksilan a

roduk sampingpa rmula selepas masa induksi untuk memberikan lebih banyak etilena glikol monoester. Pada peringkat kedua, tindak balas akan meningkat iaitu selepas kemasukkan lebih kurang 1 mol EO [6].

Rajah 2 : Spektrum FTIR bagi ALT-3EO, ALT-5EO dan ALT-7EO.

Selepas tindak balas, pepejal asid laurik yang asalnya berwarna putih telah bertukar kepada cecair yang berwarna kuning keemasan. Hasil analisis daripada FTIR menunjukkan kehadiran

da jarak

asid laurik di sebelah

Peratus penukaran produk telah ditentukan dengan menggunakan teknik HPLC. Daripada analisis kromatogram, peratus penukaran produk bagi asid laurik teretoksilat hampir mencapai 100 % seperti yang tercatat dalam Jadual 1 di bawah dan pada Rajah 3 menunjukkan kromatogram HPLC bagi asid laurik teretoksilat. Puncak pada masa penahanan 6.174, 6.222 dan 6.237 minit adalah komponen monoester yang merupakan komponen utama dalam ALT manakala puncak pada masa 2.777, 2.779 dan 2.780 minit adalah komponen diester.

Jadual 2 : Peratus penukaran produk melalui analisis HPLC.

Produk Bilangan mol EO Masa penahanan (min)

Peratus penukaran produk

kumpulan ester melalui regangan C=O pada jarak gelombang 1700 cm-1 dan ikatan O-H pagelombang 2500 – 3450 cm-1. Analisis ini telah mengesahkan persamaan tindak balas pengetoksilan

O Mangkin O Bes || C11H23COOH-H + n H2C CH2 C11H23 -CO-[CH2-CH2-O]n-H Asid laurik EO Asid laurik teretoksilat Persamaan 6

- 5.644 - 3EO 6.237 99.32 % 5EO 6.222 99.24 %

Asid laurik teretoksilat

(ALT) 7EO 6.174 81.49 %

(a) (b)

(c) (d)

Rajah 3 Kromatogram HPLC bagi (a) asid laurik, (b) ALT-3EO (c) ALT-5EO dan (d) ALT-7EO

eupayaan pembuihan dan kestabilan pembuihan

uih dikenali sebagai penyerakan yang diha gas buih dalam sesuatu cecair. Dalam detergen, jumlah buih yang terbentuk biasan bagai penentuan terhadap keberkesanan

etergen tersebut [7]. Buih yang stabil terbentuk apabila surfaktan terjerap ke dalam permukaan udara/air dengan molekul tersusun membentuk struktur lamella. Interaksi antara kumpulan hidrofilik surfaktan dalam susunan dual lapisan (bilayer arrangement) juga memberikan kesan terhadap kestabilan pembuihan selain interaksi terhadap permukaan surfaktan [8]. Secara umum, surfaktan tidak berion memberikan sifat pembuihan yang rendah. Ia juga dapat memberikan tahap pembuihan yang berbeza dengan ciri yang berbeza. Sebagai contoh, terdapat surfaktan yang memberikan kestabilan buih yang baik dan ada juga surfaktan yang mempunyai sifat buih yang mudah runtuh dengan cepat.

K B silkan daripada

ya dianggap sed

0

20

40

60

80

3 EO 5 EO 7 EO

Ket

ingg

ian

100

120

140

160

180

Laurik asid teretoksilat

bui

h (m

l)

0 minit 5 minit

Rajah 4 : Keupayaan pembuihan dan kestabilan pembuihan bagi asid laurik teretoksilat

Hasil ujian ke atas ALT-3EO, ALT-5EO dan ALT-7EO menunjukkan bahawa keupayaan pembuihan meningkat mengikut peningkatan bilangan mol EO. Dengan menggunakan Persamaan 2 dan 3,

estabilan buih bagi setiap surfaktan didapati berbeza. ALT-5EO adalah lebih stabil berbanding ALT-EO dan ALT-7EO. Keadaan ini berbeza seperti apa yang pernah dilaporkan sebelum ini bahawa elikatan cecair yang tinggi akan memberikan kestabilan buih yang tinggi . Ini kerana kelikatan cecair

yang tinggi akan mengurangkan pembentuka h besar yang mudah pecah melalui enggabungan buih-buih kecil [9]. Namun begitu ujian ini agak sukar dijelaskan kerana kestabilan

garuhi oleh banyak faktor seperti ketegangan permukaan, taburan saiz gelembung

antu proses enyingkiran kotoran daripada fabrik. Ia melibatkan pengemulsian, pemelarutan dan daya penolakan ntara fabrik dan partikel kotoran [11].

Keupayaan detergen boleh dibahagikan kepada pembasahan ke atas fabrik yang dibasuh engan menggunakan larutan detergen atau sabun, penyingkiran kotoran daripada permukaan fabrik

am larutan stabil. Dalam air pembasuhan, sabun atau detergen mampu

k3k

n buih-buipbuih turut dipenudara, kemasukkan udara dalam gelembung, kelikatan permukaan, elastik Gibbs, pengaliran cecair dari lemella, reologi penjerapan lapisan, tekanan luar dan suhu [10].

Keupayaan Detergesi ALT

Rajah 5 : Peratus keupayaan penyingkiran kotoran oleh ALT Keupayaan detergen adalah merujuk kepada kemampuan sesuatu surfaktan dalam memb

0

22 23 24 25 26 27 28 29

% P

enyi

ngki

ran

koto

ran

3 EO 5 EO 7 EOSurfaktan tidak berion

pa

ddan mengawal kotoran dal

meningkatkan keu n pem an ju mudah menembusi fabrik apai kotoran. Oleh yang demikian, penyingkiran kotora ula [12]. Ujian ke atas sampel ALT-3EO, ALT-5E dan AL bah -5EO mempunyai keupayaan deter baik. K daan ini dipengaruhi oleh struktur molekul surfaktan. EO da ALT-5E l su dalah berbentuk monomer dan molekul i enjerap ukmengarah ke permukaan air. Oleh kerana bilanga rantai E ALT toran m keterlarutannya yang lebih berban Walaupun ALT-7EO mempunyai bilangan mol EO y un kehadirannya dalam 100ml air menjadikan ia agak tepu dan men babkan pemb anyak misel. Keadaan ini menyebabkan hanya sedikit sahaja molekul surfaktan yang terjerap ke permukaan kotoran untuk ditanggalkan. Oleh itu pencucian yang lebih baik an pekata[13]. Dalam keadaan ini, ALT-5EO memberikan pencucian yang lebih baik. K n hidrofilik-lipofilik (Hydrophilic-Lipophilic Balance, HLB) Residu yang tertinggal semasa proses pencucian boleh membe p kebobahan pencuci. Dalam sistem akueus, nilai HLB y tinggi akan an kehadira u yang sedikit selepas melalui pr an. Ta han lagi, p yang baik juga boleh diperolehi daripada surfaktan yang mempunyai bi an EO ujian ini, nilai HLB dikira berdasarkan Persamaan 5 dan didapati nilainya meningkat berdasarkanm l EO daripada 3-7.

Jadual 3 menunjukkan asid laurik teretoksilat dengan nilai EO 3, 5 dan 7 mempunyai nilai H g-masing 10.66, 12.62 dan 13.90. N HLB ahawa surfaktan ini cenderung untuk bertindak sebagai agen pembasahan, pengemulsi minyak dalam air dan bahan cuci/detergen.

Jadual 3 : Asid laurik teretok HLB

urfaktan tidak berion Berat molekul

bahagian hidrofilik Berat molekul bagi

molekul HLB

payaa basahan d ga dengan n telah berm

untuk menc

O T-7EO,menunjukkan awa ALTgen yang lebih ea

n panjang rantai EO dan

O, struktur moleku kotoran d

Bagi ALT-3ni akan m

rfaktan ake perm

n aan engan bahagian

O lebih tinggi bagi hidrofilik

-5EO, koudah ditanggalkan kerana ding ALT-3EO.

ang lebih tinggi, namye entukan b

adalah y g menggunakan ke n yang sedikit

eseimbanga

rikan kesan terhada lehan sesuatu angmba

memberikembilasan

n residoses pembilas

lang yang tinggi. Dalam peningkatan bilangan

o

LB masin ilai ini menunjukkan b

silat dan nilai

SLaurik asid teretoksilat 3 EO

177 332 10.66

Laurik asid teretoksilat 5

12.62 EO

265 420

Laurik asid teretoksilat 7

13.90 EO

353 508

K Kajian ini telah berjaya menghasilka ion berasaskan tindak balas pengetoksilan t yak n HPLC menunjukkan wujudnya komponen su n juga nilai penukaran produk yang t eperti keupayaan pembuihan, keupayaan detergen dan HLB melaporkan bahawa surfaktan ini mempunyai kuasa pembuihan yang baik dan stabil, kuasa pencucian yang s sesuai digunakan seba an bahan

Penghargaan

esimpulan

n surfaktan tidak bererhadap asid laurik daripada min kelapa sawit. Hasil pencirian menggunakan FTIR da

rfaktan yang dikehendaki dainggi. Ujian-ujian surfaktan s

ederhana dan gai agen pembasahan, pengemulsi minyak dalam air dcuci/detergen.

MOSTE ‘Ministry of Science Technology and Innovation of Malaysia’ geran penyelidikkan IRPA 09-02-02-0033 dan Advanced Oleochemical Technology Division AOTD. Rujukan

1. Ovalles, C., Bolivar, R., Cotte, E., Aular, W., Carrasquel, J., Lujano, E. (2000) “Novel

Ethoxylated Surfactans from Low-value Refinery Feedstockc” Fuel. 80. 575-582. 2. Shahidi, F. (2005) “Bailey’s Industrial Oil and Fat Products”. 6th Ed, John Wiley and Sons,

Inc.New York. Ms 27-29. 3. O’Lenick, A.J., Jr., dan Parkinson, J.K. (1996) “A Comparison of The Ethoxylation of A

y Alcohol, Fatty Acid and Dimethiconol” J. Am Oil Chem Soc. 73. 63-66. Fatt4. Liana, L., (2003 Okt 7-8) 3rd “Global Oils and Fats Business Forum 2003 : Green Palmbased

Baby Products” California. 5. Wilson. A.J. (1989) Foams: Physics, Chemistry and Structure. Springer-Verlag. Great Britain. 6. http://www.zenitech.com/documents/castor_oil.pdf capaian tahun 2005 7. Davidsohn. A & Milwidsky. B.M. 1978. Synthetic Detergents. 6th edition. John Wiley & Sons Inc, New York. 8. Lim W.H. and Salmiah A. (2001) Surface Tension, Foaming and Detergency Properties of Mixed

Alpha-sulphonated Methyl Esters Derived From Palm Stearin with Some Commercial Sufactants. Journal of oil palm research. Vol. 13 No. 1, p 75-83.

9. http://www.tramfloc.com/antifoam-select.doc capaian tahun 2005 0. Karsa D.R. (1988) Industrial Applications of Surfactant. The Royal Society of Chemistry,

London. M 481 anen 0 S es n o a s e u ct. V ensk Oc on ekniska Hogskolan (KTH). 1 . G (1984) Shreve’ em Process us s. d c G -H In1 p://ww em yquestion.com

1s 1 .

1. PiispPro

. P. S. (2 02) ynth is a d Characterizati n of Surf ctant Bas d on Nat ral du

2. Austintt

et. T.

ep h K st. Kungls Ch

Tical Ind trie 5th E . M raw ill, c.

3. h w.ch istr ia hu 01 lmberg, K. (2000) “N tural urf ts” . 6. 148-159. 1 , A 0 n 1 in o a f

e ny1 a ( ) a h r / 4 8

capa n ta n 20 5 4. Ho a S actan Curr Opin Colloid Interface Sci5. Behler . (2 00 Ju 20-2 ) “F al C nference CTVO-net : New Oleochemic l Sur actants”.

Bonn. GcMurr

rmay, J.,

. 6. M 2 000 “ gOr nic C e tmis y th” 5 E Ud, S BA, ro sok C e.ol M 4s 1 5-4 .

NITRATE AND OS A CONTENTS AND QUALITY OF WELL WATE NR -E T D R TS F L T

Noor Wahida Mahasim , Ahmad Saat , Zaini Hamzah , Rita Rohaizah Sohari ,

haniza Hasliza Abdil Khali2

1 lty p ci Universiti Teknologi MARA, 404 ha m

ern l Ed ation Cent

n ti logi MAR m e 7 40200 Shah Alam

*

7 m m e

PH PH TE R I NO TH AS ERN IST IC O KE AN AN

1 2* 1 2

K

Facu of Ap lied S ences50 S h Ala

2Intiversi

ationaTekno

uc re (INTEC) pus SU A, Ka ksyen 1

Author for corrail:

espondence ad183Fax: 03-5522 065, e- ah @salam.uitm. du.my

A he north-e d o o nt % e a r r l ftheir domestic u ally e l ed within th icultur es, such as tobacco, paddy, r io ds e s t e ti ecially related l c fertilizers, may pollute the well either through runoff or underground transportation. A study was carried out on fifteen wells in the district of Bachok, Pasir Puteh and Machang to determine the well water quality as well as the nitrate and phosphate contents of the water samples. sa ng w on ice, one in y October 2004 (representing dr aso

2005 (representing rainy season sampling). Data for turbidity, temperature, DO, and pH ere determined in-situ, while the nitrate and phosphate contents, BOD and COD were determined in laboratory. Water uality Index (WQI) of the samples was determined based on the method suggested by the Interim Water Quality Standard

sia. The study found that nitrate contents ranged between 0.01 to 2.42 mg/L in rainy season and between 0.3 mg/L in dry season. The corresponding phosphate contents for rainy and dry seasons are ranging

respectively. In general, WQI of all the wells studied fall into class III or IV.

lima belas buah telaga di daerah Bachok, Pasir Puteh dan Machang, untuk enentukan kanduangan nitrat dan fosfat dan kualiti air telaga-telaga berkenaan. Pensampelan dijalankan dua kali, iaitu pada

2004 ( mewakili musim kering) dan akhir Januari 2005 (mewakili musim hujan). Data untuk kekeruhan, suhu,

(meningkat) di musim hujan di banding musim kering. Berdasarkan yang menyeluruh sebelum boleh dianggap sesuai untuk

egunaan bekalan air awam.

nitrat.

n the importance of good health among Malaysian, drinking debating subject and important issue in Malaysia [1]. Demand

bstract. In t astern istrict f state f Kela an almost 40 of th popul tions a e still elying on wel water or ses and consumption. Gener rubbe

, the wells. Ther

aris pos

ocatibility

e vici activi

nity of agres, esp

al activitito appplantat n and orchar hat th ication of

hemical

The mpli as d e tw earl y se n sampling), and the end of JanuarywQ(INWQS) for Malaynon detectable tobetween 0 – 2.2 mg/L and 0.5 – 1.5 mg/L However, WQI values of all the wells improved (increased) in wet season as compared to dry season. Based on the INWQS, these classes of water required extensive treatment before being regarded as suitable for public water supply. Key words: Well-water, WQI, phosphate, nitrate. Abstrak. Di timur laut negeri Kelantan Darulnaim, hampir 40% penduduk masih bergantung kepada air telaga untuk kegunaan domestik dan minuman. Amnya, kebanyakkan telaga terletak berdekatan dengan kawasan aktiviti pertanian seperti penanaman tembakau, padi, getah dan dusun. Dengan in terdapat kemungkinan aktiviti pertanian tersebut akan mencemar air telaga, terutamanya berkaitan penggunaan baja kimia, yang akan masuk ke telaga melalui aliran air atau perpindahan bawah tanah. Satu kajian telah dijalankan ke atas mawal OktoberDO dan pH ditentukan in-situ, manakala kandungan nitrat, fosfat, BOD dan COD ditentukan di dalam makmal. Indeks Kualiti Air (WQI) bagi sample-sampel yang dikaji ditentukan berdasarkan Interim Water Quality Standard (INWQS) for Malaysia. Kajian ini mendapati kandungan nitrat berjulat dari 0.01 ke 2.42 mg/L semasa musim hujan, dan antara tidak dapat dikesan dan 0.3 mg/L di musim kering. Kandungan fosfat di musim hujan dan musim kering pula masing-masing berjulat 0 – 2.2 mg/L dan 0.5 – 1.5 mg/L. Pada amnya nilai WQI bagi semua telaga dikaji jatuh dalam Kelas III dan IV. Walau bagaimanapun, nilai-nilai WQI bertambah baik

ranan INQWS air dalam kelas-kelas ini memerlukan rawatansak Kata kunci: Air telaga, WQI, fosfat,

Introduction

In line with the increasing awareness owater quality is becoming an increasingfor good quality water is ever increasing. Moreover the global demand in water consumption has doubled since 1940, and expected to be doubled again within twenty years [2]. With this kind of demand and the inability of the relevant authorities to supply processed cleaned water, majority of people in less developed areas resort to consuming untreated raw well water.

The majority of people living in these less developed areas involved in agriculture and farming field in chemicals in order to obtain higher yields and faster

hate and nitrate in runoff water ].

related risks may happen at higher concentration [7]. Thus, this ay me the reason to concern about the concentration of phosphate and nitrate in water.

s in Malaysia still utilized untreated well water for their drinking and ther domestic purposes, it is interesting to study the concentrations of phosphate and nitrate in well

their relation to the water quality index.

ampling

r was first rinsed with the respective well water before being used in the collection rocedures. After in-situ analysis, the water sample in the container is kept in closed cooler box at ice mperature, before being transported to chemical analysis laboratory. While in the laboratory the

amples were kept at 4 oC until further analyses.

Analysis In-situ measurements were carried out on the water samples parameters of pH, temperature, dissolve oxygen (DO) and turbidity. Other parameter measurements were carried out in laboratory. The Water Quality Index (WQI) was calculated using the method used by Mohd Talib Hj Latiff et al., [9], based on the formula suggested by the Department of Environment, Malaysia [10]. Table 2 summarizes the instruments and methods used in determining the magnitudes of the respective parameter. Table 1. Sampling points.

activities. Each year they cover their growing crops. They spray their fields with increasing amount of fertilizers – containing phosphates and nitrates. The excess fertilizers eventually will find their way into pools and ponds and wells. [3, 4]. Besides fertilizers, phosphate salts used in detergents may also contribute to phosphate accumulation in well water. Animal wastes also contribute to phosp[5

Phosphate and nitrate are nutrient for plant growth. However they can also be the primary cause of lake (well) enrichment leading to the growth of algae and weeds. This process is known as eutrophication. The presence of algae and weeds will affect the water quality index. In fact the presence of 10 ppm nitrate-nitrogen in drinking water can cause methemoglobinemia (inability to use oxygen) in infants [6] and other healthm Although the presence of nitrate and phosphate in groundwater in agricultural areas has become the main concern in various countries [5, 8] not many study has been carried out in Malaysia. Since many households in agricultural areaowaters and

Methodology

Sampling Area The study covered three districts, Bachok, Pasir Puteh and Machang, in Kelantan. From each district, five wells were selected. The depth of the wells ranged between 30 to 40 feet. However, the water volume in each well depends on various factors, such as season, location from river, height (elevation) from sea level. In general, water volume increases during rainy season. Table 1 summarizes the well location, usage and type of plantation around the wells. Majority of the wells were used as drinking water as well as other domestic usage such as washing, bath and cooking. SSampling was done twice, one in early October 2004 (representing dry season), and the other at the end of January 2005 (representing wet season). Water samples were collected using ‘water theft’ coupled to a 1-liter plastic sample container, at a point about 15 cm from surface. The plastic containeptes

District Code Location Elevation (m)

Usage Plantation

B1 N06o 07.314’ E102o 21.245’

8 Drinking, Domestic, Watering

Tobacco

B2 N06o 08.165’ E102o 21.075’


Tobacco

Bachok B3 N06o 08.118’ E102o 21.135’


Tobacco

B4 N06o 06.634’ E102o 20.118’


Paddy

B5 N06o 06.488’ E102o 19.412’

5 Abandon Paddy

P1 N05o 55.961’ E102o 18.587’

16 Drinking, Domestic Paddy

P2 N05o 55.491’ E102o 19.009’


Pasir Puteh P3 N05o 55.513’ E102o 19.134’

25 Watering Orchard

P4 N05o 55.513’ E102o 19.134’


P5 N05o 55.500’ E102o 19.053’

23 Abandon Paddy

M1 N05o 51.951’ o

32 Drinking, Domestic PadE102 12.781’

dy

M2 N05o 51.932’ E102o 12.453’

45 Watering Rubber

Machang M3 N05o 51.700’ E102o 13.804’

Drinking, Domestic Paddy 36

M4 N05 51.661’ E102o 13.987’

38 Drinking, Domestic Paddy o

M5 N05o 51.654’ E102o 13.519’


Table 2. Methods used to determine nitrate and phosphate, and the various parameters in the study.

Parameter/Ions Instruments and Method Nitrate HACH quick programme 355, DR 2000 Spectrometer Phosphate HANNA Phosphate High Range ISM, HR HI 93717 pH Portable pH meter, model WP-81, TPS Temperature, oC Portable Temperature meter, model WP-81, TPS Dissolved Oxygen (DO), mg/L HANNA portable DO probe Tu irbid ty, NTU HANNA portable turbidity meter To

r tal Suspended Solid (TSS), mg/L Total non-filterable residue, dried at 103 – 105 oC, using

Whitmann GF/C filteCh cmg/L H DR 2010 Spectrometer

emi al Oxygen Demand (COD), Digestion. COD Reactor MERCK TR-420. Measured using HAC

Bio(BO ),

chemical Oxygen Demand mg/L

HACH BOD track sample and HACH incubator D

N- 3 DR 2000 NH , mg/L HACH quick programme 380, coupled to HACHSpectrometer

Results of the study for the fifteen wells are shown in Table 3 and Table 4 for wet and dry season respectively. Although, there was temporal variation between wet season and dry season sampling,

Results and Discussion

the aver oC. However, there is observable variation of te en samples ranging between 25.5 C to 30.7 oC during wet season and between 26.9 C and 28.8 C in dry season. This may be attributed to the loc me of sampli Nitrate Nitrate contents ranged between 0 Generally well water samples in Bachok district contained highe r districts. The locations of the wells studied in Bachok district are within the vicinity of the tobacco plantations and paddy fields. Being very soluble in water, nitrate from chemical fertilizers used in the plantation and fields can be transported into the wells ater during rainy season. These concentration, however are lower than the limit of 10 mg/L suggested by the Interim Water Quality Standard of Malaysia (INWQS). During dry season, the concentrations of nitrate are relatively lower in the well water studied. In some samples nitrate are even non-detectable.

Table 3. Wet Season (Sample collected at the end of January 2005)

M5

age temperature of the samples between the two sampling periods are identical, 27.8 mperature betwe o

o o

ation of the wells, either under shaded area or in the open areas, as well as the ting, morning or afternoon.

.01 to 2.42 mg/L in wet season.r nitrate than samples from any othe

either vertically or horizontally with the rainw

B1 B2 B3 B4 B5 P1 P2 P3 P4 P5 M1 M2 M3 M4 Nitrate, mg/L

0.23 1.28 0.22 0.32 2.42 0.07 0.03 0.01 0.76 0.01 0.03 0.10 0.01 0.35 0.21

Phosphate,mg/L

nd 0.9 0.4 0.9 2.2 0.4 nd nd 1.4 nd nd 0.9 1.0 1.5 1.1

pH 6.9 7.8 7.0 8.1 6.3 6.7 6.6 5.9 6.1 6.8 6.5 5.9 5.2 5.8 5.5 Class I I I I IIA I I III IIA I I III III III III DO, mg/L 1.41 1.37 1.25 0.65 1.03 3.14 1.83 1.31 1.84 1.02 1.11 2.24 1.26 1.52 1.91 Class IV IV IV V IV III IV IV IV IV IV IV IV IV IV COD, mg/L 40.9 35.1 30.5 27.2 37.1 41.9 31.1 25.5 29.4 33.6 32.2 33.0 36.5 39.2 33.1 Class III III III III III III III III III III III III III III III BOD, mg/L 0.6 5.0 4.0 6.2 13.0 1.4 1.7 1.8 5.8 2.4 5.8 3.1 3.8 0.8 3.6 Class I III III IV V IIA IIA IIA III IIA III IIB IIB I IIB N-NH3, mg/L

0.19 0.32 0.45 0.79 0.30 0.33 0.67 0.40 0.16 0.44 0.29 0.41 0.02 0.22 0.25

Class IIA IIB III III IIA IIB III IIB IIA IIB IIA IIB I IIA IIA TSS, mg/L 15.5 13.4 6.5 6.32 9.21 3.7 5.9 13.5 5.3 14.6 3.4 4.6 2.8 2.4 3.1 Class I I I I I I I I I I I I I I I TDS, mg/L 76.2 78.0 53.0 100.7 56.9 62.3 16.1 27.6 20.4 35.7 14.5 82.5 38.7 33.3 26.2 Class I I I I I I I I I I I I I I I Turbidity, 0.51 0.55 0.60 0.63 0.54 0.61 1.11 0.93 0.63 0.74 0.53 0.92 0.61 0.50 0.53 NTU Class I I I I I I I I I I I I I I I Temp. (oC)

28.9 30.7 28.7 28.8 28.3 25.5 27.7 27.2 27.1 27.0 26.5 27.9 27.8 27.3 27.5

WQI Value

65.5 63.0 49.6 49.2 66.9 57.1 47.7 48.4 48.6 58.8 57.1 49.3 49.6 49.9 47.5

OVERALL CLASS

III III IV IV III III IV IV IV III III IV IV IV IV

Table 4. Dry season (Sample collected at the end of October 2004)

B1 B2 B3 B4 B5 P1 P2 P3 P4 P5 M1 M2 M3 M4 M5 Nitrate, mg/L

nd 0.1 nd nd 1.0 nd nd nd nd 2.0 0.1 0.1 0.3 0.2 0.2

Phosphate, 1.0 1.0 0.5 1.1 1.2 0.9 1.5 1.1 1.5 0.6 0.6 1.4 1.4 1.7 1.3 mg/L pH 5.5 6.8 5.5 6.9 5.5 6.4 5.9 5.4 5.1 6.4 4.7 6.8 4.3 5.1 5.0 Class III I III I III IIA III III III IIA V I V III IV DO, mg/L 3.45 1.93 1.03 4.61 1.86 5.64 2.92 1.50 2.25 1.70 0.99 3.55 3.18 2.06 1.70

Class III IV IV III IV IIB IV IV IV IV V III III IV IV COD, mg/l 26.4 20.1 17.9 15.7 21.7 9.1 6.8 5.9 7.9 7.1 7.3 5.4 13.6 11.6 8.4 Class IIB IIA IIA IIA IIA I I I I I I I IIA IIA I BOD, mg/L

6.8 11.8 8.7 10.3 9.2 27.4 17.3 9.5 12.7 19.4 11.3 12.8 11.5 13.7 13.0

Class III V V III IV V IV IV IV V V III III III III N-NH3 (mg/L)

0.42 0.58 0.06 1.23 0.48 0.11 0.46 0.51 0.72 0.85 0.51 0.59 0.35 0.47 0.16

Class IIB IIB I IV IIB IIA IIB IIB IIB IIB IIB IIB IIB IIB IIA TSS, mg/L 13.6 12.9 4.2 5.3 12.2 4.3 7.8 13.8 7.9 13.2 3.6 2.1 1.6 3.7 2.4 Class I I I I I I I I I I I I I I I TDS, mg/L

113.5 121.0 42.6 98.3 90.1 86.0 65.4 24.2 23.0 53.1 20.3 67.1 16.8 29.6 14.7

Class I I I I I I I I I I I I I I I Turbidity (NTU)

0.51 0.58 0.50 0.71 0.61 0.57 1.56 1.76 0.83 0.93 0.64 1.23 0.76 0.61 0.59

Class I I I I I I I I I I I I I I I Temp. (oC)

28.1 28.3 28.3 28.0 27.2 28.3 28.4 27.8 27.3 27.4 27.3 28.8 26.9 27.6 27.1

WQI Value

56.2 54.1 37.4 44.0 50.9 53.0 41.2 36.6 36.5 48.7 28.5 31.3 34.5 36.6 30.6

OVERALL CLASS

III III IV IV IV III IV IV IV IV V IV IV IV V

Phosphate The maximum phosphate concentration in the samples studied is 2.2 mg/L during wet season and 1mg/L during dry season. In some samples phosphate are non-detectable. There is no correlation trenbetween concentration duri

.7 d

ng dry and wet season. However, generally samples from Machang district her concentration of phosphate. Phosphate is not soluble in water, but when applied to

il it will get binds to the soil particles, thus it will not be transported easily through leaching or ashing together with water in the soil profiles. Therefore, although phosphate may originated from emical fertilizers applied to the plantation soil, the concentration trends shown by nitrate is not

observable in the case of phosphate.

wet season pH of the well water studied ranged between 5.2 to 8.1, with an average of 6.5. While season the well water samples become more acidic, with pH ranging between 4.7 and 6.9,

in

to

for .

Chemical OxGeneral

to ple

ized

contained higsowch

PH Value Induring drywith an average of 5.7. Based on the INWQS the wet season average falls into Class I, while the dry season falls into Class III category. This observation might be attributed to the great reduction water volume in the wells during dry season.

Dissolved Oxygen, DO Dissolved oxygen the water samples studied ranged between 1.02 mg/L to 3.14 mg/L and averaged1.53 mg/L during wet season. The average increased to 2.56 mg/L in dry season, ranging between 0.99 to 5.64 mg/L. Generally this falls into Class IV category. High DO for both seasons wassample P1, with 3.14 mg/L and 5.64 mg/L in dry and wet season respectively

ygen Demand, COD ly the COD measurements were higher in all the wells during rainy season than during dry

season. The average COD for the fifteen wells during rainy season was 33.8 mg/L, and improved12.3 mg/L in dry season. Although the maximum value of 40.9 mg/L was recorded for water samfrom well B1 during rainy season, this value is still below the 50 mg/L limit of Class III standardin INWQS.

BiochemIn wet se g/L at well B5. Well B5 is within the vicinity of a p field, and is abandoned. The average BOD increases in dry season to /L. R s sh O ell water samples in dry season exceeded the standard value of 6 mg/L (Class III) of INQ Nitrogen-Ammonia, N-NH3On average during wet season the nitrogen-ammonia concentration ranged between 0.02 – 0.67 mg/L. These concentrations are below the INQWS limit (for Class III) g/L. Except for well B4, identical trend is also observed during dry season. However, fo entration of 1.23 mg/L is beyond the INQWS limit. Generally, the nitrogen-ammoni ion of the wells shows reduction in value during we ason. Total Suspended Solids, TSS All of the well water studied either during wet or dry season fall into TSS Class I, with wet and dry season average of 8.4 mg/L and 7.2 mg/L respectively. This shows that the well water studied posed no problems in terms of TSS. Turbidity As turbidity is closely correlated to TSS, the study found that all the well water (either during wet or dry season) fall into Turbidity Class I. Physical observation also showed that all the water samples

ere very transparent in nature. In wet season the turbidity range between 0.50 – 1.11 NTU, while in .

Water Quality Index, WQI Based on the WQI values the study found that the majority of the well water samples fall into Class

S ive

able 3 and Table 4, it can be seen that the main contributing and affecting WQI values are the DO, COD and BOD. The pH values contribute a significant

role during dry season in influencing the WQI values. A comparative analysis for wet and dry season parameters was also carried out. Generally, it was found that the quality of well water studied improved during wet season. This can obviously be seen in Figure 1 where the averages of the respective parameters studied were compared for wet and dry season.

ical Oxygen Demand, BOD ason, average BOD of the fifteen wells is g/L, with a maximum value of 13.0 m 3.9 m

addy 13.0 mg esult ow that the B D of all the w

WS.

of 0.9 mr B4 the conca concentrat

t se

wdry season the range is 0.50 – 1.76 NTU

IV or V. The general trend showed that the WQI values decreased during dry season. Only wells B1 and B2 maintained the Class III category during wet as well as dry season. According to the INWQclassification only Class III and below are suitable as water supply, and that needs extenstreatment. From Tparameters on the

Figure 1. Com

6.5 5.7

1.53

2.56

33.8

12.3

3.9

13.0

0.350.50

14.7

7.2

48.1 57.7

0.660.83

27.8 27.8

0.400.50

1.07 1.12

53.9 41.3

0.1

1.0

10.0

100.0

Units

pH DOCOD

BODN-N

H3TS

STD

S

Turb

idity

Temp

Nitrate

Phosp

hate

WQI valu

e

WetDry

parison on the average of the parameters studied during wet and dry season.

les studied are still below the suggested limit, inimal. In general, the study has shown that

ble as water supply based on the INWQS index and nt. The low DO level and high COD and BOD

e classification of the well water samples to between ore acidic, and thus play an important role as

proved during wet season.

oviding the research grant for the stud rant No.: 600-IRDC/ST 5/3/938). References

1. Pillay, M.S., Talha, M.Z., 2003; Drinking Water Quality Issues; Water and Drainage Conference, K.L. 2. Karr, J., Mannusen, J., McKnight, D., Naiman, R., Stanford, J., 1995; Freshwater Ecosystems and Their

Management: A National Initiative; Science, Vol. 270, 27. 3. Barber, L., Beneke, A., Breedlove, B., 2002; Nitrate and Phosphates Levels in Pfeffer Park Stream; Natural

System I, Fall 2002, Miami University. 4. Hooda, P.S., Edwards, A.C., Anderson, H.A., Miller, A., 2000; A Review of Water Quality Concerns in Livestock

Farming Areas; The Science of the Total Environment, Vol. 250, Issues 1 – 3, 143 – 167. 5. Gymer, R.G., 1977; Chemistry in the Natural World; D.C. Heat & Company, USA; 571p. 6. Rosen, C.J., White, D.B., 1999; Preventing Pollution Problems from Lawn and Garden Fertilizers; Note FO-2923-

GO, College of Agricultural, Food, and Environmental Sciences, University of Minnesota, USA. 7. NECi, 2000; Nitrate: Health Risks to Consumers; The Nitrate Elimination Co., Inc, USA, 3p. 8. Thornburn, P.J., Biggs, J.S., Weier, K.L., Keating, B.A., 2003; Nitrate in Ground waters of intensively agricultural

areas in coastal Northeastern Australia; Agriculture, Ecosystem & Rnvironment, Vol.94, Issue 1, 49 –58. 9. Mohd. Talib Hj Latiff, Zulfahmi Ali Rahman, Jasni Yaakob, Ruzaidah Yusof, 2004; Cirian Fiziko-kimia air perigi

di kawasan Selandar, Melaka; MJAS, Vol. 8, No. 1; 87 – 92. 10. jabatan Alam Sekitar (JAS), 1991; Environment quality report, 1990; Kementerian Sains, Teknologi dan Alam

Sekitar, Kuala Lumpur.

Conclusion

The nitrate and phosphate contents of all the sampindicating the effect of fertilizers on the wall water is monly six out of the fifteen wells studied are suitaclassification, and that need further extensive treatmeare the main contributing factors attributed to thClass III and Class V. In dry season the water become mwell in determining the class. The water quality im Acknowledgement: The authors wish to thanks IRDC of UiTM for pr y (G

AKTIVITI 226Ra DAN 228Ra PADA PERMUKAAN SEDIMEN BAGAN LALANG,

O SIEW YEW, ZAHARUDDIN AHMAD2 dan CHE ABD. RAHIM MOHAMED1

SELANGOR.

NIO

Pusat Pengajian Sains Sekitaran Dan Sumber Alam Fakulti Sains Dan Teknologi

Universiti Kebangsaan Malaysia 43600 Bangi, Selangor, Malaysia

corresponding author: [email protected]

Malaysian Institute for Nuclear Technology2

Key words: 226R a, s ment

ABSTRAK

Sebanyak enam stesen sampel sedimen telah dipilih di Sungai Sepang Kecil, Selangor pada bulan Mac,

September dan Oktober 2004. Hasil kajian mendapati bahawa terdapat perbezaan yang bererti antara masa

persampelan bagi aktiviti 226Ra dan 228Ra (P < 0.01). Purata aktiviti pada bulan Mac mencatatkan nilai tertinggi,

iaitu masing-masing dengan aktiviti 161.30 Bq kg-1 dan 466.88 Bq kg-1 bagi 226Ra dan 228Ra. Manakala aktiviti

isotop radium pada bulan September dan Oktober pula masing-masing mencatatkan nilai purata 24.77 Bq kg-1

dan 69.22 Bq kg-1 bagi 226Ra serta 73.13 Bq kg-1 dan 1284.58 Bq kg-1 bagi 228Ra. Kesan Monsun Timur Laut

mungkin merupakan faktor yang mendorong aktiviti isotop radium yang lebih tinggi ketika persampelan bulan

Mac. Hasil kajian memperolehi bahawa sedimen di Bagan Lalang adalah jenis berpasir dan mempunyai variasi

saiz yan

4 for

hich show the average activities 161.30 Bq kg-1 and 466.88 Bq kg-1, respectively. Meanwhile, 226Ra activities

obtai

e

ar.

a, 228R edi

g terhad. Di samping itu, didapati bahawa isotop radium adalah lebih terjerap dengan sedimen yang

bersaiz antara 63 – 125 µm yang biasanya mengandungi kandungan feldspar alkali yang tinggi.

ABSTRACT

Six stations had selected from Sungai Sepang Kechil, Selangor during Mac, September and October 200

sediment analysis. The results showed a significant difference among the 226Ra and 228Ra activities (P < 0.01)

with sampling period. The highest activities of 226Ra and 228Ra have obtained during the sampling on Mac,

w

ned on September and October are in the average of 24.77 Bq kg-1 and 69.22 Bq kg-1, respectively.

Average activities of 228Ra are 73.13 Bq kg-1 and 1284.58 Bq kg-1, respectively for September and October.

Northeast Monsoon effect might cause the higher activities of radium isotopes during sampling on Mac.

Sediments from Bagan Lalang are sandy type with a limited size variation. Furthermore, radium isotopes ar

more adsorbed on the particles sediments between size 63 – 125 µm, which usually rich in alkaline feldsp

PENGENALAN

Sifat radiologi isotop radium yang membahayakan kesihatan awam merupakan salah satu

faktor ia sering kali dikaji oleh para saintis. Di samping itu, setengah hayat isotop radium

semulajadi (223Ra, 224Ra, 226Ra dan 228Ra) yang berbeza dari beberapa hari hingga 1600 ta

mencetuskan ia sesuai digunakan sebagai penyurih semulaja

hun

di dalam pelbagai bidang seperti

proses percampuran dalam sistem akues serta kajian kronologi dalam lautan dan tasik (1).

Selain itu, hubungan a ai untuk mengkaji fluks dan

kadar percampuran air daripada daratan dengan air laut dan estuari serta menyiasat

ukaan (2, 3). Manakala perubahan pekali

jerapan (adsorption coefficient) di antara radium dengan air tawar dan air masin telah

mengak rung

lam

eh

a

BAHAN DAN KAEDAH

alkan

oleh Kerajaan Selangor pada tahun 1990-an (5). Projek “Sepang Gold Coast” dan “Sepang

Water

al 1) dijalankan di enam stesen yang ditentukan

seperti yang ditunjukkan dalam Rajah 1 dan Jadual 1. Sungai Sepang Kecil dipilih sebagai

kawasan kajian kerana ia dapat memaparkan sistem aliran yang membezakan anntara air

payau dengan air laut.

ntara isotop-isotop radium juga sesu

pertukaran antara air bawah tanah dengan air perm

ibatkan radium terikat kuat dengan butiran sedimen dalam air tawar, malah cende

terlarut dalam air masin. Keadaan ini disebabkan oleh radium lebih cenderung terjerap da

bahan terampai dengan kekuatan ionik menigkatkan dan kepekatan partikel menurun. Ol

yang demikian, keterlarutan radium adalah lebih tinggi di kawasan estuari dan persisir pantai

(4). Tujuan kajian ini dilakukan adalah untuk melihat taburan aktiviti isotop 226Ra dan 228R

di permukaan sedimen kawasan Bagan Lalang, Selangor serta mengkaji kesan saiz partikel

terhadap isotop radium.

Lokasi kajian dan persampelan

Pantai Bagan Lalang terletak berdekatan dengan kawasan Lembah Kelang dan diperken

City” yang diperkenalkan oleh Permodalan Negeri Selangor Berhad (PNSB) dengan

CNI dijangka akan menggunakan tanah seluas 4621 ekar, iaitu pinggir Sungai Sepang Kecil

dan Sungai Sepang Besar serta pinggir pantai Bagan Lalang hingga ke Tanjung Sepat (6).

Oleh yang demikian, salah satu sebab kajian ini dilakukan di Sungai Sepang Kecil adalah

untuk menghasilkan satu data pangkalan sebelum ia diperbangunkan.

Sebanyak tiga kali persampelan (Jadu

JADUAL 1 Stesen-stesen persampelan sedimen di sekitar Sungai Sepang Kecil, Bagan Lalang.

Stesen Kod Latitud (U) Longitud (T)

1 BL1 02o36’55’’ 101o41’07’’

2 BL2 02o36’35’’ 101o40’20’’

3 BL3 02o36’30’’ 101o39’19’’

4 BL4 02o36’05’’ 101o38’05’’

5 BL5 02o36’11’’ 101o36’56’’

6 BL6 02o36’06’’ 101o35’38’’

Sampel sedimen permukaan dasar laut diambil pada setiap stesen kajian dengan

Ponar Grab. pH setiap sampel diukur dengan pH meter (model 210Aplus, Thermo Orion) di

lapangan. Seterusnya, sampel sedimen disimpan dalam beg plastik dan dibawa ke makmal

untuk analisis lanjutan.

Analisis kajian

Ketika di makmal, sampel sedimen dikeringkan dengan ketuhar pada suhu 60oC. Porositi (Ф)

sampel sedimen dicatatkan. Setreusnya ketumpatan sedimen dikira dengan menggunakan

persamaan 1(7).

RAJAH 1 Stesen-stesen kaji Sel r. angoan di Bagan Lalang,

101o34’T 101o35’T 101o36’T 101o37 1 39’T 101o40’T 101o41’T

2o38’U

2o37’U

2o36’U

2o35’U

① ②

④ ⑤ ⑥

0 1KM

U

o38’T 101o

③

’T 10

248

Ketumpatan sedimen (ρs) = 2.6__ (1)

(1-Ф)

Seterusnya, sampe nakan mortar dan

diayak dengan pengayak elektronik bagi mene en. Diameter (d)

sampel sedimen yang bersaiz 25 63 µm dan d < 63 untuk

analisis yang seterusnya. Pengelasan partikel sedimen dilaklukan menggunakan skala

Wentworth. Skala ini digunakan secara meluas dan partikel saiz sedimen ditukar kepada unit

phi (Ø) (8

Ø - mm (2)

Penguku statist g lazim nakan dalam skala Wentw ad

Pur ) = (Ø 16 + Ø 50 + Ø 84)

l sedimen kering ditumbuk dengan menggu

ntukan partikel saiz sedim

: 125 <d< 0 µm, <d<125 µm disimpan

).

= log2

ran ik yan digu orth alah:

ata ( _ X

3 3)

Ral ) = Ø 84 –Ø 16

(

at ( σ Ø 5+ 95 –Ø

(4)

Ske s (sk) = 16 + Ø 84 - 2 Ø

4 6.6

wnes Ø 50 + + 50 Ø 5 Ø 95 - 2 Ø

2(Ø 84 –Ø 16) 2( (5)

en kering dicerna dengan asid hidroklorik. Lebih kurang 1 g sampel

sedimen dimasukkan ke dalam kaca ma dengan 1 m b 0 ml 8

M asid h oklorik bahkan. Campuran ini ditut ngan tu anaskan

atas piring pemanas selama 2 – . Set ya, h adaman dibiar sejuk dan dituras

dengan k as tura berdi r 47 m ngan saiz liang 0.45 µ

man). Hasil turasan dikeringkan atas piring panas. Bahan yang tertinggal dalam bikar

rklorik 1% untuk proses penulenan radium.

Radium ditulenkan dengan menggunakan turus pemisah kation AG 50W-X4 Resin (200-

400 mesh, Bio-rad). Di mana sampel (≈ 50 ml) dialir dalam turus pemisah kation untuk

penulenan. Kemudiannya, 200 ml asid hidroklorik 1.5 M dialirkan melalui turus. Efluen

disimpan dalam bikar dan dikeringkan atas plat pemanas. Hasil pengeringan dilarutkan

dengan asid nitrik 0.5 M (≈ 100 ml). Seterusnya, 2 ml asid sulfurik pekat ditambahkan.

Mendakan barium sulfat (BaSO4) yang terbentuk dituraskan dengan mengguna kertas turas

berdiameter 25 mm (GF/C, Whatman). Berat bersih BaSO4 dicatatkan untuk mendapatkan

Ø 95 –Ø 5)

Sampel sedim

bikar bersa l pem awa Ba2+ dan 2

idr ditam up de penu p kaca dan dip

3 jam erusn asil h

ert s yang amete m de m (G/FC filter,

What

dilarutkan dengan lebih kurang 50 ml asid pe

249

perolehan semula kimia sampel. Seterusnya, BaSO4 diletakkan atas disk stainless steel dan

dilabut dengan kertas plastik. Disk yang disiap balut dibilang dengan Spektrometer Gross

Alfa/Beta (model LB5100-W, Tennelec) setelah keseimbangan sekular radium dengan

anak-anaknya dapat dicapai (dibiarkan selama tiga bulan).

HASIL DAN PERBINCANGAN

Taburan isotop radium pada permukaan sedimen

Rajah 2 menunjukkan taburan isotop radium pada permukaan sedimen di Bagan

Lalang. Stesen 4 terletak pada mulut muara sungai mencatatkan aktiviti 226Ra dan 228Ra

tertinggi pada bulan September dan Oktober. Hal sedemikian mungkin disebabkan oleh

pengumpulan partikel sedimen yang dibawa dari sungai (semasa air surut) serta laut (semasa

air pasang). Partikel sedimen yang terkumpul mungkin mengalami penjanaan semula dan

mengakibatkan aktiviti radium pada permukaan sedimen yang tinggi di Stesen 4. Oleh sebab 228Ra mempunyai setengah hayat yang pendek (5.75 tahun), jadi penjanaan semula bagi

aktiviti 228Ra adalah lebih cepat (≅ 280 kali) berbanding 226Ra. Maka, nisbah aktiviti 228Ra/226Ra di Stesen 4 juga tinggi, iaitu lebih kurang lima.

Manakala taburan aktiviti isotop radium pada permukaan sedimen pada bulan Mac

2004 adalah hampir sekata, kecuali aktiviti 228Ra yang abnormal (870 Bq kg-1) di Stesen 6.

Faktor yang menyumbangkan aktiviti 228Ra yang tinggi di Stesen 6 adalah tidak jelas.

Aktiviti isotop 226Ra dan 228Ra (P < 0.01) pada permukaan sedimen pula

menunjukkan perbezaan yang sangat bererti dengan masa persampelan. Rajah 3 memaparkan

taburan aktiviti isotop radium pada permukaan sedimen mengikut masa peersampelan. Hasil

kajian mendapati bahawa purata aktiviti 226Ra dan 228Ra adalah maksimum pada

p

466.88 Bq kg-1. Manak eptember dan Oktober

adalah lebih rendah, iaitu dengan masing -

ersampelan bulan Mac, iaitu masing-masing dengan purata aktiviti 161.30 Bq kg-1 dan

ala aktiviti isotop radium pada bulan S

250

(a)

0

200

400

600

800

1000

1 2 3 4 5 6Stesen

Ra

(Bq

kg-1

) Ra-226Ra-228

(b)

050

100150200250300

1 2 3 4 5 6

Stesen

Ra

(Bq

kg-1

)

(c)

0

100

200

300

400

500

1 2 4 5 6

Stesen

Ra

(Bq

kg-1

)

RAJAH 2 Taburan 226Ra dan 228Ra pada permukaan sedimen ketika persampelan bulan (a) Mac, (b) September,

dan (c) Oktober.

masing mencatatkan nilai purata 24.77 Bq kg-1 dan 69.22 Bq kg-1 bagi 226Ra serta 73.17 Bq

kg-1 dan 184.58 Bq kg-1 bagi 228Ra.

251

0

100

Mac Sept Okt

Persampelan

200

300A

ktiv

iti (B

q kg

-1

400

500

)

Ra-226Ra-228

RAJAH 3 Purata aktiviti 226Ra dan 228Ra pada permukaan sedimen mengikut masa persampelan.

Pantai barat Semenanjung Malaysia mengalami musim hujan ketika Monsun Timur

aut (Mac). Partikel sedimen dari daratan dan sungai turut dibawa oleh air hujan ke estuari

an lautan. Justeru itu, terdapat input tambahan bagi aktiviti isotop radium pada permukaan

sedimen. Jadi, aktiviti isotop radium pada bulan Mac adalah lebih tinggi berbanding dengan

persampelanpada bulan September dan Oktober.

Kesan partikel saiz sedimen terhadap isotop radium

Jadual 2 menunjukkan partikel saiz dan j bagi ketiga-tiga persampelan. Secara

keseluruhannya, permukaan sedimen Bagan Lalang dikelaskan dalam kumpulan pasir. Purata

iz sed

halus). Rala lasan sedimen Bagan

Lalang adalah kurang baik, iaitu variasi partikel saiz sedimen yang diangkut atau termendak

adalah kurang. Nilai skewness (sk) pula digunakan sebagai penunjuk bagi sejarah taburan

stesen terse

ini mungkin disebabkan oleh peningkatannya partikel halus yang termendak ataupun partikel

yang kasar telah terpindah daripada stesen tersebut. Manakala bagi sampel yang mempunyai

nilai sk yang negatif merujuk kepada pemendakan partikel kasar telah berlaku di kawasan

L

d

enis sedimen

sa imen ( _ X ) adalah daripada saiz -0.83Ø (pasir sangat kasar) hingga 3.12 Ø (pasir sangat

t partikel sedimen (σ) yang besar merujuk kepada penge

partikel saiz sedimen. Sampel yang mempunyai nilai sk yang positif menunjukkan bahawa

but mengandungi lebihan partikel yang halus. Sumber kemasukan partikel halus

252

tersebut. Faktor yang mendorong kepada perubahan nilai sk adalah angin dan kesan ombak

).

Stesen ( _ X), Ø

Ralat (σ) Skew

(sk)

Porositi

(Φ) pH Kelas sedimen

(8

JADUAL 2 Pengelasan sedimen di Bagan Lalang.

Purata saiz

Mac

1 1.95 0.84 0.18 0.41 9.51 Pasir sederhana

2 2.18 1.44 -0.16 0.52 8.65 Pasir halus

3 2.13 0.64 0.07 0.74 8.76 Pasir halus

4 -0.60 1.23 -0.39 0.83 8.36 Pasir sangat kasar

5 0.26 0.63 -0.32 0.81 5.58 Pasir kasar


September

1 1.91 1.98 -0.23 0.54 7.06 Pasir sederhana

2 1.67 0.54 -0.17 0.76 7.18 Pasir sederhana

3 0.32 0.61 0.19 0.81 7.58 Pasir kasar

4 -0.83 0.90 0.21 0.77 7.54 Pasir sangat kasar



Oktober

1 1.169 1.85 0.39 0.29 6.72 Pasir sederhana

2 1.09 2.20 0.05 0.39 7.22 Pasir sederhana



6 0.01 0.75 -0.18 0.81 7.83 Pasir kasar

253

(a)16)

R2 = 0.124P > 0.05

4

12

226

-2 B

q g-1

8

Ra

(x10

00 20 40 60 80 100

% Partikel Sedimen

(b)

8

12

16

X 1

0-2 B

q g-1

)

R2 = 0.6914Ra

(

P < 0.001

00 5 10 15 20 25 30 35

% Partikel sedimen

226

(c)

R2 = 0.16020

25

30

Bq

g-1)

P > 0.05

5

10

226 R

a (X

-2

15 10

00 10 20 30 40 50 60

% Partikel sedimen

RAJAH 4 Kolerasi aktiviti 226Ra dalam sedimen Bagan Lalang dengan peratusan partikel sedimen dengan saiz

partikel (a) +2<Ø<+3, (b) +3<Ø<+ 4, dan (c) Ø>+4.

254

(a)150

200

Bq

g-1)

R2 = 0.017P > 0.05

0

50

100

0 20 40 60 80 100% Partikel sedimen

228 R

a (X

10-2

(b)

R2 = 0.388P < 0.0540

506070

10-2

Bq

g-1)

0102030

0 5 10 15 20 25 30 35% Partikel sedimen

22

8 Ra

(X

(c)

R2 = 0.01960

80

100

-2 B

q g-1

)

P > 0.0540

228

10

RAJAH 5 Kolerasi aktiviti 228Ra dalam sedimen Bagan Lalang dengan peratusan partikel sedimen dengan saiz

partikel (a) +2<Ø<+3, (b) +3<Ø<+ 4, dan (c) Ø >+4.

Rajah 4 dan 5 memaparkan kesan saiz partikel terhadap isotop radium. Hasil kajian

mendapati bahawa aktiviti 226Ra (P < 0.01) dan 228Ra (P < 0.05) lebih terjerap dalam partikel

sedimen bersaiz +3<Ø<+ 4 (63-125µm). Menurut Zhang et al (9), logam alkali bumi, iaitu

barium dan strontium (mempunyai sifat yang menghampiri dengan radium) juga

20Ra

(X

00 10 20 30 40 50 60

% Partikel sedimen

m

disebabkan oleh feldspar alkali yang biasa

m

Secara ke

ketika m

m

Bagan Lalang dikelaskan sebagai jenis be

kurang. D

terjerap dalam partik

Terim

255

enunjukkan kolerasi possitif degan partikel saiz yang lebih kasar. Keadaan ini mungkin

nya wujud dalam partikel yang lebih kasar

engandungi unsur barium, strontium, rubidium dan cesium yang tinggi (10).

KESIMPULAN

simpulannya, aktiviti isotop radium pada permukaan sedimen adalah lebih tinggi

usim hujan. Air hujan merupakan agen pembawa partikel sedimen yang

engandungi isotop radium dari daratan dan sungai ke estuari dan lautan. Sampel sedimen di

rpasir dengan mengandungi variasi saiz yang

i samping itu, aktiviti isotop radium juga boleh disimpulkan bahawa ia lebih

el yang bersaiz 63 – 125 µm yang biasanya mengandungi kandungan

feldspar alkali yang tinggi.

PNEGHARGAAN

a kasih kepada MINT dan ahli makmal yang memberi bantuan dalam kajian in

RUJUKAN

1. Kim, Y.J., Kim, C.K., Kim, C.S., Yun, J.Y., Rho, B.H. 1999. Determination of 226Ra in environmental samples using high-resolution inductively coupled plasma mass spectrometry. J. Radioanal. Nucl. Chem. 240: 613-618.

2. Nour, S., El-Sharkawy, A., Burnett, W.C., Horwitz, E.P. 2004. Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin. Appl. Radiat. Isot. 61: 1173-1178.

3. Eikenberg, J., Tricca, A., Vezzu, G., Stille, P., Bajo, S., Ruethi, M. 2001. 228Ra/226Ra/224Ra and 87Sr/86Sr isotope relationships for determining inter s between ground and river water in the upper Rhine Valley. J. Environ. Radioact. 54: 133-162.

4. Rama, Moore, W.S. 1996. Using the radium quartet to estimate water exchange and ground water input in salt marshes. Geochim. Cosmochim. Act. 60: 4645-4652.

5. Dharmender, S. 2003. Rare sights at Bagan Lalang. (atas talian) http://www.allmalaysia.info/news/story. (17

i.

action

Januari 2005). 6. Sepang Gold Coast dan Sepang Water City. (atas talian)

http://www.pnsb.com.my/n_jan03.htm. (17 Januari 2005).

256

7. DiToro, D.M. 1999. Sediment Flux Modelling. New York: John Wiley & Sons. 8. Pethick, J. 1984. An introduction to coastal geomorphology. London: Edward Arnold. 9. Zhang, C., Wang, L., Li, G., Dong, S., Yang, J., Wang, X. 2002. Grain size effect on

10.

multi-element concentrations in sediments from the intertidal flats of Bohai Bay, China. Appl. Geochem. 17: 59-68.

Gotze, J. 1998. Geochemistry and provenance of the Atlendrof feldspathic sandstone in the Middle Bunter of the Thuringian basin (Germany). Chemical Geol. 150: 43-61.

257

KERADIOAKTIFAN TABII DAN KANDUNGAN LOGAM BERAT DALAM IKAN DARI SUNGAI ATOK DAN SUNGAI TAHAN ,TAMAN NEGARA PAHANG.

Muhamad bin Othman, Redzuwan bin Yahaya & Hiew Ching Ching

Program Sains Nuklear,Pusat Pengajian Fizik Gunaan,Fakulti Sains dan Teknlogi Universiti Kebangsaan Malaysia, 43600 BANGI, Selangor Darul Ehsan.

[email protected]

n otot, dikering dan ihomogenkan. Sampel seterusnya dihadamkan menggunakan asid nitrik sehingga jernih. Hasil

pekatan U-238 adalah alam julat 1.47 ± 0.006 – 6.17 ± 0.007 Bq/kg. Bagi logam berat pula 13 unsur telah dapat dikesan,

unsur-unsur tersebut adalah aluminium, argentum, arsenik, ferum, magnesium, mangan, kobalt, kromium, kuprum, plumbum, selenium, strontium an dengan Piawaian Antarabangsa (FAO) menunjukkan kandungan unsur-unsur tersebut adalah pada paras yang selamat untuk dimakan.

Abstract. This study was conducted to determ e natural radioactivity and h fish of species Puntius gonionotus, Leptobarbus hoevenii, Mytus nemurus Puntius schwanenfeldii dan Cyprinus carpio from Sungai Atok and Sungai Tahan of National Park, Pahang. The radioactivities of U-238 and Th-232 ed using gamma spect try whereas the concentrations of heavy metals were determined by Inductively Coupled Plasma Optical Emission

. Fish samples were separated into muscle and bone, dried and homogenized. amples were then digested using nitric acid until a clear solution was obtained. Result showed that

was in the range of 1.47 ± 0.006 – .17 ± 0.007 Bq/kg. Thirteen heavy metals were detected, namely aluminium, silver, arsenic, iron,

ri bahan organik dan tak organik termasuk logam berat dan bahan dionuklid. Logam berat merupakan pencemar tak organik yang berbahaya dan dapat dikumpulkan

dalam sungai yang telah lama tercemar dengan logam berat pula menunjukkan peningkatan

Abstrak. Dalam kajian ini keradioaktifan tabii dan kandungan logam berat dalam sampel ikan species Puntius gonionotus, Leptobarbus hoevenii, Mytus nemurus Puntius schwanwnfeldii dan Cyprinus carpio dari Sungai Atok dan Sungai Tahan, Taman Negara, Pahang telah ditentukan. Keradioaktifan U-238 dan Th-232 telah ditentukan menggunakan Spektrometri Sinar Gama manakala kandungan logam berat telah dianalisis menggunakan Spektrometri Emissi Optik Plasma Gandingan Teraruh (ICP-OES). Sampel ikan telah dipisahkan kepada bahagian tulang dadanalisis mendapati hanya U-238 sahaja yang ditemukan didalam ikan. Ked

dan zink. Perbanding

ine th the concentration of

eavy metal in

were analys rome

Spectrometry (ICP-OES)Sonly U-238 was found in all fish species. The activity of U-2386magnesium, manganese, cobalt, chromium, copper, lead, selenium, strontium and zinc. A comparison with the International Standard (Food and Agriculture Organization) showed that the level of heavy metal in fish from both rivers was safe for human consumption. Key words: fish, muscle, bone, U-238, River Atok, River Tahan , heavy metals.

Pendahuluan Pencemaran air kini semakin meluas akibat daripada proses pembangunan, perindustrian dan kegiatan pertanian yang kian meningkat (Kulikova et. al., 1985). Pembuangan sisa-sisa daripada kilang terus ke dalam sungai menyebabkan air sungai mengandungi bahan kimia beracun (Hargrave, 1991). Kemasukkan bahan kimia ke dalam air sungai akan menyebabkan perubahan kimia air dan mengganggu sistem akuatik. Hidupan akuatik yang tidak dapat menyesuaikan diri dengan perubahan ini akan mati dan pupus sementara bagi hidupan yang dapat menyesuaikan diri kandungan bahan kimia beracun dalam organisme akan meningkat. Bahan kimia beracun ini terdiri daraoleh jasad akuatik melalui rantai makanan. Kajian terhadap sungai yang tercemar menunjukkan kandungan logam berat tertentu meningkat didalam plankton, moluska dan algae. Kajian pada ikan di

258

kandungan zink, kuprum, plumbum, raksa dan kadmium dalam tisu otot. Kepekatan kadmium dan zink yang tinggi ditemukan pada ginjal sementara hati menunjukkan kepekatan kuprum yang tinggi (Wachs, 1985). Oleh kerana ikan merupakan sumber protin utama bagi manusia, peningkatan logam berat dalam ikan akan menjejaskan kesihatan manusia. Kajian terhadap kandungan logam berat didalam ikan di kawasan yang masih bersih menjadi penting bagi dijadikan piawaian untuk menentukan aras pencemaran. Taman Negara merupakan kawasan

erlindungan bagi tumbuhan dan haiwan didalam persekitaran semulajadi. Di dalam kawasan ini an kajian kepekatan logam

erta keradioaktifan tabii dikawasan ini boleh memberikan ukuran latar atau rujukan bagi kawasan y ng belum tercemar. Selain itu nilai yang diperolehi dapat dibandingkan dengan kawasan lain samada yang belum tercemar ataupun yang telah tercem an seumpama ini belum pernah dija tersebut (komunikasi peribadi). Selain daripada itu beberapa tempat dikawasan Taman Negara telah dibenarkan i oleh orang an seperti Sungai Tahan dibenarkan untuk dikunjungi sehingga ke kawasan Lata Berkoh. Di kawasan ini p manda dan m kawasan Sungai Keniam pula pada m sim-musim tertentu orang ramai dibenarkan untuk memancing. Pengangkutan untuk sampai kedua-dua kawasan tersebut kebanyakkannya menggunakan bot-bot yang menggunakan m ak petrol. Oleh itu kajian ini jika dilakukan secara berkala selain daripada menyediakan bacaan latar juga dapat digunakan untuk menilai kesan kemasukkan orang p kandungan uns sur surihan di dalam kawasan tersebut. B

awasanan kajian

gkus kemudian dimasukkan kedalam bekas penyejuk (Coleman) berisi ais (0° C).

psegala bentuk aktiviti pembangunan tidak dibenarkan. Oleh yang demikis

aar. Tambahan pula kaji

lankan di kawasan untuk dilawat ramai. Kawas

engunjung dibenarkan untuk mandi emancing. Diu

iny

ramai terhada ur-un

ahan dan Kaedah

K

Kajian telah dilakukan dikawasan Sungai Atok dan Sungai Tahan, Taman Negara, Pahang (lihat rajah 1). Di Sungai Atok pensampelan telah di buat di dua lokasi, lokasi pertama (SA 1) terletak 2 km dari muara sungai sementara lokasi ke 2 (SA 2) berada kira-kira 10 km dari muara sungai. Di Sungai Tahan, pensampelan juga dilakukan pada dua lokasi. Lokasi pertama (ST 1) terletak 2 km dari muara sungai sementara lokasi ke 2 (ST 2) terletak 8 km dari muara sungai. Kedua- dua buah sungai bermuara ke dalam Sungai Tembeling yang merupakan sempadan Taman Negara di sebelah Timur Laut.

Kaedah pensampelan Sampel ikan telah ditangkap dengan menggunakan jaring nilon. Jaring direntangkan mengikut kelebaran sungai dan dibiarkan selama satu malam (11jam). Ikan yang terlekat pada jaring diasingkan mengikut spesies dan dimasukkan ke dalam beg plastik. Setiap spesies diambil sebanyak tiga ekor. Ikan yang diambil dipilih berdasarkan beratnya (900 – 1000 gm). Sampel yang telah dibun

259

Rajah 1: Lokasi pengambilan sampel di Su dan han ra, Pahang.

Taman Nega Sungai Tangai Atok

260

Rawatan sampel Apabila sampai di makmal ikan-ikan dicuci bersih dengan menggunakan air udian disiang dan dibilas dengan air suling. Sampel tersebut diwapkan selama s suhu 100°C untuk emisahkan bahagian otot dan bahagian tulang. Setelah dipisahkan, kedua-dua bahagian dikeringkan sehingga berat menjadi tet ulang kemudian dihaluskan dengan pengisar dan di ayak untuk mendapatka ogen. Sampel y ihomogen ini siap untuk digunakan. Penentuan radioaktiviti dalam sampel Botol polietilina kosong ditimbang dan dicatatkan beratnya. Sampel otot dan tulang seperti persediaan diatas dimasukkan ke dalam botol tersebu imasukkan ke dalam b ut banyaknya bahan piawai yang digunakan (bahan piawai terdapat dalam botol polietilina dengan isipadu tertentu). B rikan dan ditimbang semula untuk mendapatkan berat s yang telah dimaterikan dibiarkan selama satu bulan untuk mencapai kesaimbangan sekular. Piawai yang

ntuk kajian ini adalah IAEA Standard – 134 cockle flesh.

ktiviti sampel dianalisis dengan menggunakan sistem pembilang spektrometri sinar gama. Keradioaktifan uranium-238 ditentukan menerusi puncak bismuth-214 sementara kehadiran torium-

n torium-232 ditentukan dengan menggunakan formula berikut:

at ditangkap daripada kedua-dua buah sungai tersebut. an-ikan tersebut adalah terdiri daripada species Puntius gonionotu (Lampan Jawa), Leptobarbus

oevenii (Ikan Jelawat), Mytus nemurus(Ikan Baung) Puntius schwanwnfeldii (Lampan Sungai) dan Cyprinus carpio (Ikan Lee Koh). Secara relatif didapati kandungan uranium-238 dalam ikan di Sungai Atok adalah lebih tinggi jika dibandingkan dengan Sungai Tahan. Perbezaan keradioaktifan diantara kedua buah sungai tersebut adalah 1.68 Bg/kg (lihat Jadual 1) Perbezaan ini mungkin disebabkan oleh uranium-238 yang hadir dalam bahan organik tidak banyak termendap dalam Sungai

suling. Ikan kematu jam pada

map. Sampel otot dan tn sampel yang hom ang telah d

t. Sampel d otol mengik

otol dimate ampel. Botol

d

igunakan u

A

232 dikenalpasti melalui talium-208. Keradioaktifan uranium-238 da

WS = AS x MP x WP / AP x MS Dimana WS = keradioaktifan unsur dalam sampel (Bq/kg) WP = keradioaktifan unsur dalam piawai (Bq/kg) AS = aktiviti unsur dalam sampel (b/s) AP = aktiviti unsur dalam piawai (b/s) MS = jisim sampel (g) MP = jisim piawai (g) Penentuan logam berat dalam sampel Ambil 200 mg sampel dan ditambah dengan 3 ml asid nitrik (HNO3) dan 3 ml hidrogen peroksida (H2O2). Sampel dipanaskan di dalam ketuhar mikro gelombang sehingga larutan menjadi jernih. Setelah disejukkan sampel dicairkan dengan air suling sehingga larutan menjadi 15 ml. Larutan tersebut kemudian dituraskan. Hasil turasan dimasukkan ke dalam alat Spektrometri Emissi Optik Plasma Gandingan Teraruh (Inductively Coupled Plasma-Optical Emission Spectrometry ICP-OES) untuk mendapatkan bacaan kandungan logam berat Larutan piawai yang digunakan adalah ICP Multi Element Standard Solution (IV) (Merck) Hasil dan Perbincangan Keradioaktifan uranium-238 dan torium-232 mengikut lokasi Dalam kajian ini lima spesies ikan telah dapIkh

260

261

Tahan kerana peng an bahan organik ang banyak di dasarnya. Sementara di Sungai atok pengalirannya yang perlahan memberi peluang ntuk berlakunya pemendakan bahan organik didasarnya dan sekaligus meningkatkan kandungan

uranium-238. Selain daripada itu terd dua-dua buah sungai yang dikaji. ngai ntara air di Sungai Tahan

kawa bera 6.5 – rut Dru t. al. (197 pulan metal m sang rah pada ikan brook trout adalah lebih t ika

Apakah perbezaan pH y kecil dala juga turut yumbang p um t

r tori la tidak san di d di kedu ngai ters ungkin

di sebabka 32 sukar diserap oleh ika nding d ium-238 rhadap kandungan t dalam dikawasan tersebut juga -232 adalah jauh lebih rendah daripada uranium-23 2002). abkan k rium-

dalam pun ba k jauh ah dar um-238 untuk diambil oleh i juga bukan merupakan unsur yang

38 dan Th-232 didala an me si

dioakti

aliran air di sungai ini sangat deras dan menghalang pemendakyu

apat perbezaan pH diantara keAir Supada

Atok dikawasan kajian berasan kajian

ekuri dalam in

da pada pH antara 7. 2 – 7da dalam julat

.4 sememmond e 6.8. Menu 4) pengum

dan sel da inggi pada pH 6 jdibandingkan pada pH 9. ang m kajian ini mendalam enyerapan urani -238 tidak dapa dipastikan.

Unsu um-232 pu dapat dike alam ikan a-kedua su ebut.Ini mn torium-2

orium-232 din jika diba engan uran

mendapati kepekatan torium. Kajian te

tanah8 (Norizan, Ini menyeb andungan to

232 air mahukan. Torium

han organilah

lebih rend ipada uranidiperlukan.

dan sukar

Jadual 1: Kandungan U-2 m sampel ik ngikut loka

Kera fan (Bq/kg)

Lokasi

Ura

oriumnium-238 T -232

ngai A 4.42

TH Su tok

± 0.012 Sungai Tahan

2.74 ± 0.008

TH

TH – unsur tidak dapat dikesan Kandungan uranium-238 dan torium-232 mengikut spesies ikan Kajian mengikut spesies ikan pula mendapati Puntius schwanwnfeldii mempunyai kepekatan uranium-238 yang tertinggi, iaitu sebanyak 6.17 ± 0.007 Bq/kg manakala Puntius gonionotus menunjukkan kepekatan uranium-238 yang terendah iaitu 1.47 ± 0.006 Bq/kg (Jadual 2). Kandungan uranium-238 dalam Leptobarbus hoevenii dan Mytus nemurus adalah hampir sama iaitu masing-

± 0.006 Bq/kg dan 4.74 ± 0.006 Bq/kg. Sementara dalam Cyprinus carpio kepekatan ranium-238 adalah 3.32 ± 0.008 dan nilai ini merupakan nilai kedua terendah.

ogam berat dan bahan radionuklid dalam air dapat masuk kedalam tubuh ikan melalui penjerapan

a moluska mempunyai kebolehan yang nggi untuk menumpuk logam berat di dala a jika dibanding dengan organisme akuatik ang lain (Kulikova et. al., 1985).

Dalam kajian ini tiada torium-232 ditemukan dalam semua spesies ikan.Hasil kajian ini agak berbeza dengan kajian yang telah dijalankan oleh Norsaliza (2004). Kajian beliau di Sungai Keniam dan

masing 4.13 u

Lsubstrat ke atas permukaan badan, penyerapan melalui insang dan dinding usus atau kedua-duanya sekali (Luoma, 1983) Perbezaan kepekatan uranium-238 dalam kelima-lima spesies mungkin disebabkan oleh perbezaan penjerapan logam melalui permukaan, badan atau perbezaan dalam penyerapan insang dan dinding usus. Selain daripada itu faktor yang menyebabkan perbezaan dalam kandungan uranium-238 adalah cara pemakanan dan jenis makanan yang dimakan. Ikan-ikan yang mencari makan didasar sungai berkemungkinan mempunyai kepekatan uranium-238 yang lebih tinggi disebabkan terdapat pemendakan bahan organik yang tinggi di dasar sungai. Ikan-ikan yang memakan

oluska juga akan tinggi kandungan logam beratnya keranmti m tubuhnyy

261

262

Sungai Terengan, Taman Negara, Pahang mendapati hanya torium -232 ditemukan di dalam Puntius ing 0.

(Ikan Rom) dan abiobarbus festivus (Ikan Kawan) didapati kepekatan uranium-238 adalah dalam julat 2.63 ± 0.84

hingga disebabkan ikan-ikan yang dikaji adalah berbeza ecuali Puntius schwanenfeldii.

Jadual 2

schwanenfeldii dan Cyclocheilichthys apogon (Temperas) dengan kepekatan masing-mas 57 ±0.081 Bq/kg dan 0.67 ± 0.094 Bq/kg. Sementara di dalam Osteochilus spilurusLBq/kg hingga 10.24 ± 2.84 Bq/kg dan kepekatan torium-238 adalah dalam julat 4.01 ± 0.94 Bq/kg

20.01 ± 2.84 Bg/kg. Perbezaan ini mungkin k

: Kandungan uranium-238 dan torium-232 mengikut spesies ikan

Keradioaktifan (Bq/kg)

Uranium-238

Torium-232

Spesies

s gonionotus (Lampan Jawa)

Puntiu 1.47 ± 0.006 TH Le

ptobarbus hoevenii (Ikan Jelawat) 4.13 ± 0.006 TH

M 4.74 ± 0.007 TH ytus nemurus(Ikan Baung)

Puntius schwanenfeldii (Lampan Sungai)

6.17 ± 0.007

TH

Cyprinus carpio (Ikan Lee Koh). 3.32 ± 0.008 TH

T

H tida

asil k manakala

menunj tinggi di Sungai

enunj

enurut Post (1983) kepekatan maksimum aluminium pada pH 7 adalah 3.75 mg/kg manakala pada H 9 kepekatan aluminium adalah sekurang-kurangnya 375 mg/kg. Tidak diketahui kenapa nilai luminium di Sungai Tahan agak tinggi sedangkan pH dikawasan tersebut adalah diantara 6.5- 6.8.

elatif ikan-ikan dari Sungai Atok menunjukkan kepekatan argentum, zink, kuprum,kobalt romium, plumbum dan strontium yang lebih tinggi. Sementara kepekatan arsenik, selenium, ferum,

mangan dan magnesium adalah lebih tinggi dalam sampel ikan dari Sungai Tahan. Tidak dapat pastikan apakah perbezaan ini disebabkan oleh perbezaan pH diantara kedua-dua buah sungai.

dual 3.; Kandungan logam berat dalam ikan mengikut lokasi

Kepekatan (mg/kg berat kering)

k dapat dikesan

Kandungan logam berat mengikut lokasi

ajian mengikut lokasi menunjukkan 12 unsur ditemukan dalam ikan di Sungai AtokH13 unsur pula ditemukan di Sungai Tahan(Jadual 3). Logam aluminium hanya dijumpai dalam ikan di Sungai Tahan. Secara keseluruhan unsur yang terdapat di dalam ikan di kedua buah sungai

ukkan nilai yang hampir serupa kecuali unsur kuprum yang didapati lebih Atok dan unsur ferum didapati lebih tinggi di Sungai Tahan. Secara keseluruhan kepekatan argentum dalam ikan dari kedua-dua sungai adalah palingi tinggi dan diikuti oleh magnesium dan kobalt

ukkan kepekatan paling rendah. m MpaSecara rk

di Ja

Jenis logam Sungai Atok

Sungai Tahan

Aluminium

BHP

47.84 ± 1.84

262

263

Argentum 3761.21 ± 585.32 3750.69 ± 582.29 Arsenik

1.69 ± 0.60

1.71 ± 0.62

Selenium

1.52 ± 0.53 1.77 ± 0.44

Zink

49.95 ± 1.61 46.35 ± 1.52

Kuperam 46.77 ± 0.65

55.03 ± 0.50

Kobalt

0.25 ± 0.03

0.21 ± 0.02

Ferum

4.07 ± 0.13

9.44 ± 0.63

Mangan 26.83 ± 0.33 30.39 ± 0.33 Kromium

1.23 ± 0.02

0.91 ± 0.02

Plumbum

0.39 ± 0.11

0.26 ± 0.21

Magnesium

751.45 ± 3.59

766.78 ± 8.06

Strontium

5.88 ± 0.06

5.82 ± 0.07

Kandungan logam berat dalam otot dan tulang ikan Jadual 4 menunjukkan kandungan logam berat didalam otot dan tulang ikan. Dari jadual tersebut dapat dilihat aluminium mempunyai kepekatan yang sangat tinggi di dalam otot/daging ikan iaitu sebanyak 163. 51 ± 3.28 mg/kg berat kering. Sementara zink, kromium dan strontium dalam tulang

an adalah lebih kurang dua kali ganda kepekatannya jika dibandingkan dengan kepekatan dalam tot.

epekatan unsur selenium dan plumbum dalam tulang adalah separuh daripada yang terdapat dalam

roses pencernaan dan proses asimilasi makanan tercemar. Logam berat diserap oleh inding usus dan dibahagikan ke tisu lain. Pembahagian ini dipengaruhi oleh spesies dan keadaan imia logam, kualiti makanan dan tempoh masa selepas pencernaan.

Jadual 4: Kandungan logam berat didalam otot dan tulang ikan

Kepekatan (mg/kg berat kering)

iko Kdaging ikan. Manakala kepekatan argentum, arsenik dan kobalt adalah hampir sama baik di dalam daging mahupun di dalam tulang. Kuprum, ferum mangan dan magnesium mempunyai kepekatan yang lebih tinggi di dalam sampel tulang. Kandungan logam berat dalam daging dan tulang ikan berasal daripada pengambilannya melalui makanan semasa pdk

Jenis logam Tulang Otot

Aluminium

163.51 ± 3.28

27.82 ± 4.06

Argentum

3752.77 ± 4.72

3759.11 ± 694.63

Arsenik

1.95 ± 0.52

1.45 ± 0.69

263

264

Selenium 2.04 ± 0.45 1.24 ± 0.52 Zink 61.18 ± 2.12 46.35 ± 1.52 Kuperam

56.71 ± 0.61

46.77 ± 0.65

Kobalt

0.23 ± 0.03

0.21 ± 0.02

Ferum

32.86 ± 1.37

9.44 ± 0.63

Mangan 30.50 ± 0.39

30.39 ± 0.33

1.42 ± 0.02

0.91 ± 0.02 Kromium

Plumbum 0.15 ± 0.05 0.26 ± 0.21 Magnesium

878.32 ± 7.97

766.78 ± 8.06

Strontium

7.94 ± 0.08

5.82 ± 0.07

Kandungan logam berat dalam pelbagai spesies ikan

Kandungan logam berat dalam pelbagai spesies ikan tercantum pada jadual 5. Secara keseluruhan didapati argentums menunjukkan kepekatan yang sangat tinggi di dalam semua spesies. Julat kepekatan logam tersebut adalah 3703.01±707.91mg/kg berat kering hingga 3859.44±589.29 mg/kg berat kering. Kepekatan tertinggi terdapat pada Puntius gonionotus sementara kepekatan terendah adalah pada Leptobarbus hoevenii. Unsur kedua tertinggi adalah magnesium dengan julat 644.14 ± 10.79mg/kg berat kering iaitu terdapat pada Leptobarbus hoevenii ehingga 861.99 s ± 7.21 mg/kg berat kering yang terdapat pada Puntius schwanenfeldii.Logam luminium pula hanya ditemukan pada Mystus nemurus. Kepekatan yang agak tinggi ini mungkin

ak bersisik dan memudahkan unsur

Bagi unsur zink dan kuprum kepekatan d dite pada rinus o mamasin g/kg be an g/k t ke eptertinggi bagi zink adalah pada Puntius gonionotus dan bagi kuprum pula adalah pada Lep ystus la kk dung ngan dan

aitu masing-masing 26.43 ± 0.34 mg/kg berat kering dan 1.83 ± 0.19 mg/kg erat kering. Kandungan ferum dan mangan tertinggi pula dijumpai pada Puntius gonionotus,

ring. dan 29.06 ± 0.32 mg/kg berat nsur kob t l u dan ar epekatanny am . Unsur n stro an kepekata dalam o iaitu masing 0.42 ± 0.02 mg ring dan 3.80 ± 0 /kg berat

kering rtinggi bag dua unsur ters sing-masing ditemukan pada Puntius gonionotus dan Puntius schwanenfeldii.

adisebabkan sifat permukaan badan ikan tersebut yang tidaluminium untuk dijerap.

teren ah mukan Cyp carpi sing-g adalah 39.87 ± 1.03 m rat kering d 27.54 m g bera ring. K ekatan

tobarbus hoevenii. Spesies M nemurus pu menunju an kan an maferum terendah ibkepekatannya adalah masing 32.49 ± 0.21 mg/kg berat ke

nik didapatikering. Bagi u al , p umb m kromium da

se kntium menunjukk

a hampir sama dalsemua spesiesCyprin i

n terendah us carp /kg t ke bera .04 mg. Nilai te i kedua- ebut ma

264

265

Jadual 5: Kandungan logam berat dalam ikan mengikut spesies

atan (mg/kg beKepek rat kering)

Unsur ius otus

Leptobarbus hoe

Cyprinus carpio

Mystus murus

Puntius schwanenfeldii

Puntgonion venii ne

Al TH TH TH .84 TH 47.84±1

Ag 3 589.29 3703.0 3743.72±401.01 6±749.15 3711.80±425.00 859.44± 1±707.91 3784.1

As 43 1.27±0.40 1.95±0.76 ±0.52 1.59±0.1.53±0. 1.81 74

Se .71 1.08 2.04±0.34 ±0.53 2.06±0.1.23±0 ±0.37 1.57 47

Zn 62.31±1.68 48.26±2.17 39.87±1.03 43.35±1.86 48.33±1.24

Cu 61.60±0.63 84.58±0.83 27.54±0.43 66.28±0.89 31.35±0.30

Co 0.19±0.03 0.11±0.03 0.22±0.02 0.22±0.03 0.23±0.03

Fe 32.49±0.21 TH 12.51±0.24 1.83±0.19 12.66±0.29

Mn 29.06±0.32 28.94±0.56 32.13±0.26 26.43±0.34 28.40±0.30

Cr 2.94±0.04 0.82±0.02 0.42±0.02 0.62±0.01 1.30±0.02

Pb 0.15±0.07 0.19±0.04 0.15±0.11 0.19±0.10 0.19±0.07

Mg 748.35±5.42 644.14±10.79 734.46±7.53 696.91±7.88 861.99±7.21

Sr 6.24±0.05 10.15±0.14 3.80±0.04 5.02±0.06 6.62±0.07

TH dibawah had pengesanan Hasil kajian ini jika dibandingkan dengan kajian yang telah dijalankan di Vietnam dan dengan piawaian antarabangsa mendapati semua logam dalam ikan di kedua buah sungai berada pada paras yang selamat atau lebih rendah daripada paras selamat kecuali mangan dan strontium. Kedua-dua logam ini didapati dalam semua spesies adalah lebih tinggi daripada keputusan yang ditemukan di Vietnam (Wagner & Boman, 2003). Selain itu dalam kajian ini kandungan unsur dinyatakan berdasarkan berat kering sampel, bagaimanapun kajian lain yang dijalankan menyatakan hasil berasaskan berat basah. Kepekatan logam dalam tisu ikan yang dinyatakan dalam berat kering boleh ditukar kepada berat basah dengan membahagikan nilai tersebut dengan faktor 4 hingga 6 (Khan et. al., 1987; Parsons, 1999; Romeo et. al., 1999; Lewis et. al., 2002). Kesimpulan Keradioaktifan uranium-238 dalam ikan di kedua buah sungai berada pada paras yang normal

e u

Rujukan Drummond, R. A., Olsen, G. F. & Batterman, A. R. (1974). Cold response and uptake of mercury by brook trout, Salvelinus fontinalis, exposed to mercuric compounds at different hydrogen-ion concentration. Trans. Am Fish. Soc. 103: 244-256.

sementara unsur torium-232 tidak ditemukan di dalam kes m a spesies ikan yang dikaji. Bagi kandungan logam berat pula semua spesies menunjukkan paras yang selamat atau lebih rendah daripada paras yang selamat kecuali unsur mangan dan unsur strontium. Kedua-dua unsur tersebut mungkan tersedia lebih tinggi secara alamiah menyebabkab ia ditumpuk lebih tinggi didalam ikan. Kehadiran unsur yang rendah didalam ikan menunjukkan kawasan sungai tersebut masih merupakan kawasan yang bersih

265

266

Hargrave, B. T. (1991). Impacts of man’s activities on aquatic systems. DlmBarnes, R. S. K. & Mann, K. H. (pnyt.). Fundementals of aquatic Ecology. U.S: Blackwell Science. Khan, A. H., Ali, M., Biaswas, S. K. & Hadi, D. A. (1987). Trace element in marine fish from the Bay

of Bengal. Sci. Total Environ. 65: 121–130. Kulikova, I., Seisuma, Z., & Legsdina, M. (1985). Heavy metals in marine organisms.Dlm Salanki,

J.(pnyt.). Heavy Metals in Water Organisms. Akademiai Kiado, Budapest, 141-151.

Lewis, M. A., Scott, G. I. Bearden, D. W., Quarles, R. L. Moore, J., Strozier, E. D., Sivertsen, S. K., Dias, A. R. & Sanders, M. (2002). Fish tissue quality in near-costal areas of the Gulf of Mexico receiving point source discharges. Sci. Total Environ. 84: 249-262.

Louma, S. N. (1983). Bioavailability of trace metalsto aquatic organisms – a review. Sci. Total

Environ. 38: 1-22 Nor n sedi(Ke angi, 32-34.

orsaliza Zakaria (2004). Radioaktiviti dan kandungan logam berat dalam ikan di Sungai Keniam i Terengan, Taman Negara, Pahang. Tesis Sm. Sn. (Kep.), UKM, Bangi, 21–23.

ement concentration in whole fish from North Lantau waters, Hong

e

agner, A. & Boman, J. (2003). Biomonitoring of trace element in muscle and liver tissues of freshwater fish. Spectrochemica Acta Part B: Atomic Spectroscopy. 58(12): 2215–2226.

.

izan Abd. Majid .(2002). Keradioaktifan tabii dan kandungan logam berat dalam tanah damen di kawasan Sungai Atok dan Sungai Tahan, Taman Negara, Pahang. Tesis Sm. Sn. p.). UKM. B

N

dan SungaParson, E. C. M. (1999). Trace el

Kong. ICES J. Mar. Sci. 56: 791–794. Post, G. W. (1983). Textbook of Fish Health. T. F. H. Publication Inc. Ltd., Hong Kong. Romeo, M., Siau, Y. Sidoumou, Z. & Gnassia-Barelli, M. (1999). Heavy metal distribution in

different fish species from the Mauritania coast. Sci. Total Environ. 232: 169–175. Wachs, B. (1985). Bioindicators for the heavy metal load of river ecosystem. Dlm. Salanki, J. (pnyt.).

Heavy M tals in Water Organisms. Akademiai Kiado, Budapest,179–180. .W

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TINDAK BALAS PENGKOMPLEKSAN ASID-3-(3-BENZOILTIOUREDO) PROPIONIK

DENGAN BIS[ASETATOTRIFENILFOSFINARGENTUM(I)] DAN KOBALT(II)KLORIDA

Pusat Pengajian Sains Kimia & Teknologi Makanan, Fakulti Sains & Teknologi

ABSTRAK

Tindak balas sebatian (I)] dengan asid-3-(3-benzoiltiuredo)propionik ompleks [(PPh3)2Ag(µ-C11H12O3N2S)2Ag(PPh3)2 mi tindak balas gantian oleh sebatian asid-3-(3-benzoiltiouredo)propionik. Kajian kristalografi sinar-X mendapati

roduk ini mempunyai sistem triklinik dengan kumpulan ruang Pī, a = 12.691(3) Ǻ, b = 13.080(3) Ǻ, 7(3) Ǻ, α = 94.888(5) o , β = 93.818(6) o dan γ = 97.254(5) o. Dua molekul asid-3(3-

do)propionik berkoordinat kepada kedua-dua atom argentum melalui atom sulfur

NURZIANA NGAH, BOHARI M. YAMIN & MOHAMMAD BIN KASSIM

Universiti Kebangsaan Malaysia, Bangi

kompleks bis[asetatotrifenilfosfinargentum dalam pelarut kloroform telah menghasilkan k]. Dalam tindak balas ini, kumpulan asetat telah mengala

pc = 14.26benzoiltiourekumpulan tiono dan oksigen kumpulan karboksilik membentuk kompleks dimerik. Tindak balas asid-3-(3-benzoiltiouredo) propionik dengan kobalt(II) klorida dalam pelarut etanol telah menghasilkan kompleks [Co(C11H11N2O3S)2(C2H5OH)2]. Kajian mendapati atom kobalt berkoordinat kepada 2 molekul asid-3-(benzoiltiouredo)propionik melalui atom S dan 2 molekul etanol melalui atom O dalam sekitaran 4 koordinatan. Kumpulan karboksilik telah mengalami nyahproton menjadikan sebatian tiourea sebagai ligan negatif ekacas. Kajian kristalografi sinar-x mendapati hablur ini mempunyai sistem triklinik dengan kumpulan ruang Pī, a = 8.779(2) Ǻ, b = 9.094(2) Ǻ, c = 9.118(2) Ǻ, α = 78.592(4) o , β = 72.443(4) o dan γ = 75.895(4) o. PENGENALAN Sebatian asid-3-(3-benzoiltiouredo)propionik (Rajah 1) merupakan sebatian benzoiltiourea terbitan asid amino β-alanin. Sebatian ini menarik kerana terdapat beberapa tapak untuk berlakunya tindak balas pengkompleksan dengan logam, iaitu kumpulan tiono (C=S), karbonil (C=O) dan karboksilik (COOH). Kertas ini membincangkan tindak balas pengkompleksan sebatian asid-3-(3-benzoiltiouredo)propionik dengan kompleks bis[asetatotrifenilfosfinargentum(I)] dan kobalt(II)klorida.

C

O

NHC

S

NHH2C

CH2C

O

HO

1 2

689 23

45

7

1011

1

1: Struktur asid-3-(3-benzoiltiouredo)propionik Rajah

267

268

EKSPERIMEN Asid-3-(3-benzoiltiouredo)propionik disediakan mengikut kaedah yang dilaporkan oleh Yusof & Yamin [1]. Asid-3-(3-benzoiltiouredo)propionik dan bis[asetatotrifenilfosfinargentum(I)] dipanaskan dalam pelarut kloroform dan dibiarkan memekat pada suhu bilik. Sedikit aseton dan etanol ditambah untuk mencairkan larutan. Larutan ini dituras dan dibiarkan menghablur pada suhu bilik. Dalam

ndak balas dengan kobalt(II)klorida pula, larutan akues CoCl2 ditambah setitis demi setitis ke dalam rutan asid 3-(3-benzoiltiouredo)propionik yang telah dicampurkan sedikit larutan KOH. Mendak

merah jambu yang terbentuk dituras dan dikeringkan. PERBINCANGAN Tindak balas asid-3-(3-benzoiltiouredo)propionik dengan sebatian bis[asetatotrifenilfosfinargentum(I)], filtrat jernih terhasil didapati memberikan hablur bersinar tanpa

arna setelah dibiarkan selama ½ jam pada suhu bilik. Mikroanalisis unsur CHNS mendapati hablur ang terbentuk mempunyai unsur karbon, hidrogen, nitrogen dan sulfur. Analisis mikrounsur

menunjukkan peratus unsur yang hampir sama, kecuali peratus unsur karbon yang agak berbeza (Jadual 1) berdasarkan formula [(PPh3)2Ag(µ-C11H O3N2S)2Ag(PPh3)2]. Spektrum inframerah hablur menunjukkan regangan bagi υ(C=O), υ(C-O), υ(C=S) dan υ(C-N) berbanding ligan bebas asid-3-(3-benzoiltiouredo)propionik (Jadual 2). Analisis spektrum 1H RMN menunjukkan perubahan yang agak ketara bagi δ(N1) dan δ(N2), manakala spektrum 13C RMN pula menunjukkan perbezaan yang besar bagi δ(C8) dan δ(C11) berbanding ligan bebas (Jadual 3). Dalam tindak balas dengan kobalt(II)klorida, penambahan larutan aques kobalt(II)klorida kepada asid-3-(3-benzoiltiuredo)propionik yang telah dicampur dengan larutan KOH telah memberikan mendakan merah jambu secara perlahan-lahan. Analisis mikrounsur CHNS mendakan merah jambu menunjukkan persetujuan peratus karbon, hidrogen, nitrogen dan sulfur dengan jangkaan (Jadual 1).

nalisis spektrum inframerah menunjukkan perubahan nombor gelombang bagi υ(C=S) berbanding ligan bebas (Jadual 2) menunjukkan kemungkinan koordinatan berlaku pada atom sulfur. Kajian RMN terhadap sebatian ini tidak menunjukkan sebarang isyarat. Oleh yang demikian, ia bersifat paramagnet. JADUAL 1: Takat lebur dan analisis mikrounsur sebatian

Peratus unsur

tila

wy

12

A

Sebatian Takat lebur(oC) C H N S

[(PPh3)2Ag(µ-C11H12O3N2S)2Ag(PPh3)2]

180.7-181.5 56.36 (63.87)

4.65 (4.79)

2.86 (3.17)

2.90 (3.62)

[Co(C11H11N2O3S)2(C2H5OH)2] 17 48.98 (49.19)

5.66 (5.90)

7.62 (8.19)

8.78 (9.38) 4.5-176.3

*(nilai jangkaan)

ADUAL 2: Mod getaran spektrum inframerah sebatian

cm-1 C11H12O3N2S1

[(PPh3)2Ag (µ-C11H12O3N2S)2

Ag(PPh3)2]

[Co(C11H11N2O3S)2 (C2H5OH)2]

J Sebatian Frekuensi,

υ(C=S) 660.0 612.4 619.0 Υ(C=O) 1671.6 1677.7 υ(C-O) 1029.4 1094.2 1397.6

υ(C-N) 1227.4 1272.2 1240.1

268

269

JADUAL 3: Anjakan kimia 1H dan 13C RMN bagi [(PPh3)2Ag(µ-C11H12O3N2S)2Ag(PPh3)2]

Sebatian

Anjakan kimia, ppm C11H12O3N2S1

[(PPh3)2Ag(µ-C11H12O3N2S)2 Ag(PPh3)2]

δ(N1) 11.33 7.74 δ(N2) 11.05 7.46

δ(C1-C6) 128.5-133.08 129.45-135.96 δ(C7) 168.19 167.52 δ(C8) 180.35 207.22 δ(C9) 40.69 42.81 δ(C10) 32.39 34.63 δ(C11) 173.10 179.45

Kajian kristalografi sinar-X Kajian kristalografi sinar-X sebatian [(PPh3)2Ag(µ-C11H12O3N2S)2Ag(PPh3)2] mendapati ia mempunyai sistem triklinik dengan kumpulan ruang Pī, a = 12.691(3) Ǻ, b = 13.080(3) Ǻ, c = 14.267(3) Ǻ, α = 94.888(5) o , β = 93.818(6) o dan γ = 97.254(5) o. Kedua-dua atom argentum terkoordinat kepada 2 atom fosforus kumpulan trifenilfosfin, oksigen dan sulfur sebatian asid-3-(3-benzoiltiouredo)propionik, menjadikan geometri di sekitar atom argentum tetrahedron terherot dengan sudut di antara 85.10(14) dan 116.67(6)o. Rajah 1 menunjukkan struktur molekul dengan skema penomboran.

RAJAH 2 Struktur [(PPh ) Ag(µ-C H O N S) Ag(PPh ) ] dengan skema penomboran

melalui atom S1 dan 2 molekul 2H5OH melalui atom O4 (Rajah 2). Geometri atom kobalt adalah segi empat planar dengan sudut

0.0(1)o. Dalam penyelesaian struktur ini, ketaktertiban atom C12 belum dapat diselesaikan sehingga kini.

3 2 11 12 3 2 2 3 2yang digunakan

Kajian kristalografi sinar-X mendaapti hablur kompleks [Co(C11H11N2O3S)2(C2H5OH)2] bersistem triklinik dengan kumpulan ruang Pī, a = 8.779(2) Ǻ, b = 9.094(2) Ǻ, c = 9.118(2) Ǻ, α = 78.592(4) o , β = 72.443(4)o dan γ = 75.895(4)o ]. Molekul ini bersifat sentrosimetri berpusat pada atom kobalt, di mana atom kobalt berkoordinat kepada 2 molekul C11H12O3N2S1CS1-Co1-S1A dan O4-Co1-O4A sebanyak 18

269

270

RAJAH 3 Struktur [Co(C11H11N2O3S)2(C2H5OH)2] dengan skema penomboran yang digunakan

KESIMPULAN Kompleks [(PPh3)2Ag(µ-C11H12O3N2S)2Ag(PPh3)2] terhasil dalam tindak bis[asetatotrifenilfosfinargentum(I)] dengan asid-3-(3-benzoiltiouredo)propionik. Dalam tindak balas ini, kumpulan asetat sebatian bis[asetatotrifenilfosfinargentum(I)] telah diganti oleh sebatian asid-3-(3-benzoiltiouredo)propionik membentuk kompleks dimerik. Pengkompleksan pada kedua-dua atom

ENGHARGAAN

pada Pusat Pengajian Sains Kimia & Teknologi Makanan, Fakulti Sains Teknologi UKM di atas kemudahan penyelidikkan yang disediakan. Jutaan terima kasih kepada

829

argentum melibatkan atom oksigen dan sulfur satu ligan secara jejambat. Tindak balas dengan CoCl2.6H2O pula, sebatian asid-3-(benzoiltiouredo)propionik telah mengalami deprotonasi pada kumpulan karboksilik. Pengkompleksan 2 molekul anion tersebut dan 2 molekul etanol dengan 1 molekul ion Co2+ ini menjadikan keseluruhan kompleks [Co(C11H11N2O3S)2(C2H5OH)2] ini bercas neutral.

P Ucapan terima kasih ke

Kementerian Sains, Teknologi & Inovasi (MOSTI) kerana bantuan kewangan yang dihulurkan melalui Skim Biasiswa National Science Fellowship (NSF). RUJUKAN [1]Yusof, M. S. M. & Yamin, B. M. 2003. 3-(3-benzoylthiouredo)propionic acid. Acta Cryst. 2003. o828-

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271

SYNTHESIS, STRUCTURAL CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF ORGANOTIN(IV) DERIVATIVES WITH CARBOHYDRAZIDE -

BIS(SALICYLALDEHYDE) (H4CBS): X-RAY CRYSTAL STRUCTURE OF [Me2Sn(H2CBS)]

M. A. Affan1*, Y. Z. Liew 1, Fasihuddin B. Ahmad1, Bohari M. Yamin 2 and Mustaffa B. Shamsuddin

3

1Resource Chemistry, Faculty of Resource Science and Technology Universiti Malaysia Sarawak, 94300 Kota Samarahan,

Sarawak, Malaysia

School of Chemical Sciences and Food Technology Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

3Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai

Johor Darul Takzim, Malaysia Abstract Five new organotin(IV) complexes of carbohydrazide-bis(salicylaldehyde) [H4CBS, (1)] ligand with RnSnCl4-n (n = 1, 2) have been synthesized in the presence of base and refluxing in 1:2:1 molar ratio (metal:base:ligand). All organotin(IV) complexes (2-6) have been characterized by different physico-chem r conductivity measurements, elemental analysis, UV-visible, IR and 1H NMR spectral studies. All organotin(IV) complexes (2-6) are non electrolytic in nature. Among them, dimethyltin(IV) complex (2) is also characterized by X-ray crystallography diffraction analyses. In the solid state, the carbohydrazone ligand (1) exist as the keto tautomer but in solution in the presence of base and organotin(IV) chloride(s), it conver nol tautomer and coordinated to the tin(IV) atom in its deprotonated enolate form. X-ray cryst ethyltin(IV) complex [Me Sn(H CBS)] (2), is five-coordinate and has a distorted trigonal-bipyramidal geometry

its phenolic-O, nolic-O and imine-N atoms. The general bond length order is oxo < phenolato < enolato. The Sn-O

(enolato) bond is longer than Sn-O (phenolato Sn-O (carboxyla ucture of [Me2 2 h c group P2(1)/c wi .143(2) Å, c = 12.203(2) Å, α = 9 = 106.063(3)°, γ = 90°, V = 1750.4( 9 Mg/m3. The IR and 1H NMR data are consistent with all the organotin( milar geometry. The biological activities of the ligand [H4CBS, (1)] and it s have been studied by screening the compounds against several

tain degree of biological activities.

2

ical techniques like mola

ted to the eallographic analysis shows that the dim

2 2with the ligand coordinated to the tin(IV) as a tridentate dinegative fashion throughe

) bond by ~0.08 Å and is identical with Sn(H CBS)] (2) is oclinic wit spa e te) bond. The crystal str mon

th a = 13.163(3) Å, b = 11 0°, β6), Z = 4 and Dcalc = 1.68IV) derivatives having sis organotin(IV) complexe

ed cerbacteria. The complexes show

Keywords: Carbohydrazone ligand; Organotin(IV) compounds; Crystal structure; Biological activities. Corresponding author: Tel.: +6082-679235; fax: +6082-672275 E-mail address: [email protected] Introduction

ydrazides and hydrazones H have interesting ligational properties due to the presence of several otential coordination sites. The chemistry of carbohydrazide compounds has been studied by Swamy

and Siddalingaiah [1]. Variety of metal complexes of symmetrical dihydrazones derived from iocarbohydrazides have been synthesized and their stereochemistry have been reported in the teratures [2-3] and potentially useful biological activities [3]. However, the coordination chemistry f the corresponding carbohydrazide derivatives is less explored [4]. Complexes of the

p

thlio

271

272

carbohydrazide with non-transition metal ions such as organotin(IV) have not received as much ttention. In view of the importance of tin compounds in medicinal chemistry and biotechnology [5]

and as part of ou -hydrazones [6-7] t here the synthesis and characterization of the new ca ylaldehyde) ligand (Scheme 1) and of its organotin(IV) complexes (Scheme 2) and together with the X-ray methyltin(IV) complexes [Me2Sn(H2C (2). The antimicrobial properties of ds are evaluated.

ar on going work on tin , we repor

rbohydrazide-bis(salic crystal structure of di

these compounBS)]

H

O

C

N

H2N NH2

NH

H

O C

HO

Carbohydrazide Salicylaldehyde

+ 2

Ab

2H2O

s. ethanol

Keto form

Scheme 1 Experimental Synthesis Chemicals were obtained from Fluka and Aldrich and were used without further pwere analytical grade and purified by standard methods [8]. The C, H, N elemperformed on a Carlo Erba EA 1108 model analyser. Infrared spectra were recordeShimadzu 8201 PC Fourier-Transform Spectrometer. 1H NMR spectra were recsolution on a Bruker 300 FT-NMR spectrophotometer. Electronic spectra wShimadzu 2401 PC UV-Visible spectrophotometer.

Enol form

272

+

urification. Solvents ental analyses were d as KBr disc using orded in DMSO-d6 ere recorded on a

273

Carbohydrazide-bis(salicylaldehyde) ligand (H4CBS) [C15H14N4O3] (1)

solution of Me2SnCl2 (0.002 mole, 0.439g) in methanol (10 L) was added dropwise to the potassium salt of ligand solution, the color of the solution became

otassiu chloride (KCl) was removed by filtration and the filtrate was evaporated to obtain the

lid. The yellow micro-crystals were filte hed with hexane and dried in vacuo ight. Single crystals suitable fo diffraction studies were obtained by slow

chloroform-hexane solution (1:1) .51%. M. p. = 218-220 °C. Found: C, 3; N, 12.56%. Calc. for C15H12N4O C, 45.88; H, 4.05; N, 12.59%. λmax (nm)

MF): 266, 343, 398. IR (νmaxcm-1 (KBr): 1604 (C=N)+(C=C), 1318 (C–O, phenolic), 960 (N–N), n–C), 566 (Sn–O), 470 (Sn–N). 1H NMR ( MSO-d6): δ 11.41 (br, OH), δ 10.89 (s,

(s, N=CH)), δ 6.63–7.93 (m, a δ 0.68 (s, Sn-CH3).

(H2CBS) [Bu2Sn(C15H12N4O3)] (3)

lex (3) was synthesized in a similar way as in (2), using dibutyltin(IV) dichloride (0.002 mole, ), instead of dimethyltin(IV) dichloride. Yield = 68.51%. M. p. = 225-227 °C. Found: C,

N, 10.55%. Calc. for C15H12N4O : C, 52.02; H, 6.02; N, 10.55%. λmax (nm) axcm-1 (KBr): 1604 )+(C=C), 1323 (C–O, phenolic), 952 (N–N),

1H NMR ( z, DMSO-d6): δ 11.45 (br, OH), δ 11.05 (s, 1 (s, N=CH)), δ 6.65–7.89 (m, a ), δ 0.79 (t, 6H, (-CH3) of butyltin), δ 1.18

.26-1.45 (m, 4H, (- (m, 4H, -CH2-Sn). Ph2Sn(H2CBS) [Ph2 15 12N4O3)] (4)

mplex (4) was prepared similarly to complex ing diphenyltin(IV) dichloride (0.002 mole, .688 g) instead of dimethyltin(IV) dichloride. Yield = 64.33%. M. p. = 208-210 °C. Found: C, 56.65;

H, 3.88; N, 9.87%. Calc. for C15H12N4O3Ph2Sn: C, 56.69; H, 3.87; N, 9.85%. λmax (nm) (DMF): 266, 342, 398. IR (νmaxcm-1 (KBr): 1600 (C=N)+(C=C), 1325 (C–O, phenolic), 960 (N–N), 600 (Sn–C), 520 (Sn–O), 460 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.48 (br, OH), δ 11.15 (s, NH) δ 8.17 & 8.38 (s, N=CH)), δ 6.70–7.62 (m, aromatic and Sn-C6H5 protons). MeSnCl(H2CBS) [MeSnCl(C15H12N4O3)] (5) The procedure described above for (2) was followed for the preparation of (5), with methyltin(IV) trichloride being used instead of dimethyltin(IV) dichloride and the refluxing time for this preparation was 2-3 hours. Yield = 65.46%. M. p. = 205-206 °C. Found: C, 41.19; H, 3.25; N, 12.05 %. Calc. for C15H12N4O3MeSnCl: C, 41.23; H, 3.22; N, 12.02%. λmax (nm) (DMF): 267, 341, 398. IR (νmaxcm-1 (KBr): 1610 (C=N)+(C=C), 1340 (C–O, phenolic), 952 (N–N), 590 (Sn–C), 560 (Sn–O), 472 (Sn–N).

A mixture of carbohydrazide (0.005 mole, 0.450 g) and salicylaldehyde (0.0010 mole, 1.221 g) in absolute ethanol (30 mL) were heated under reflux for 3-4 hours. The reaction mixture was allowed to cool down to room temperature for half an hour. Then the white precipitate was filtered off and washed several times using absolute ethanol. The crystalline white solid obtained was purified by recrystallization from hot absolute ethanol and dried in vacuo over P2O5 overnight. Yield = 70.05%. M. p. = 178-180 °C. Found: C, 59.20; H, 4.59; N, 18.40%. Calc. for C15H14N4O3: C, 59.21; H, 4.61; N, 18.42%. λmax (nm) (DMF): 262, 292, 328. IR (νmaxcm-1 (KBr): 1681(-C=O), 1616 (C=N)+(C=C), 1272 (C–O, phenolic), 946 (N–N). 1H NMR (300 MHz, DMSO-d6): δ 10.86 (br, OH), δ 8.44 (s, N=CH), δ 7.69 (br, CONH), δ 6.62–7.27 (m, aromatic-H). Me2Sn(H2CBS) [Me2Sn(C15H12N4O3)] (2) Carbohydrazide-bis(salicylaldehyde) (0.002 mole, 0.596g) was dissolved in hot absolute methanol (20 mL) under nitrogen atmosphere with potassium hydroxide (0.0042 mole, 0.236g) previously dissolved in methanol (15 mL). The colour of the solution changed from off-white to yellow. The resulting mixture was refluxed for one hour and amdarker. The resulting solution was refluxed for four hours and allowed to cool. The precipitatedp myellow so red off and wasover P2O5 overn r X-ray evaporation of . Yield = 6945.91; H, 4.0 3Me2Sn:(D608 (S 300 MHz, DNH) δ 8.14 & 8.43 romatic-H).

Bu2Sn Comp0.688 g52.00; H, 6.03; 3Bu2Sn(DMF): 267, 340, 396. IR (νm

Sn–O), 440 (Sn–N). (C=N

590 (Sn–C), 560 ( 300 MHNH) δ 8.15 & 8.4 romatic-H(m, 4H, (-CH2) of butyltin), δ 1

Sn(C HCH2) of butyltin) δ 1.55-1.64

(2), usCo0

273

274

1H NMR (300 MHz, DMSO-d6): δ 11.42 (br, OH), δ 10.96 (s, NH) δ 8.14 & 8.44 (s, N=CH)), δ 6.64–7.90 (m, aromatic-H). δ 1.14 (s, Sn-CH3). PhSnCl(H2CBS) [PhSnCl(C15H12N4O3)] (6) The procedure described above for (5) was followed for the preparation of (6), with phenyltin(IV) trichloride being used instead of methyltin(IV) trichloride. Yield = 64.23%. M. p. = 213-215 °C. Found: C, 49.10; H, 3.63; N, 10.22 %. Calc. for C15H12N4O3PhSnCl: C, 49.15; H, 3.66; N, 10.25%.λmax (nm) (DMF): 268, 340, 399. IR (νmaxcm-1 (KBr): 1608 (C=N)+(C=C), 1330 (C–O, phenolic), 956 (N–N), 615 (Sn–C), 520 (Sn–O), 451 (Sn–N). 1H NMR (300 MHz, DMSO-d6): δ 11.44 (br, OH), δ 11.10 (s, NH) δ 8.18 & 8.39 (s, N=CH)), δ 6.72–7.62 (m, aromatic and Sn-C6H5 protons). X-ray Crystallography Yellow single-crystal of (2) (size 0.34 × 0.32 × 0.15 mm) was grown from chloroform-hexane mixture at the room temperature. The measurements were erformed at 273 (2) K on Siemen SMART CCD diffraction using graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). Orientation matrix and unit cell parameters were obtain ered reflection. The crystals are monoclinic, space group P2(1)/c with a = 13.163(3), b = 11.143(2), c = 12.203(2) Å, α = 90°, β = 102.064(3)°, γ = 90°, V = 1750.4(6) A3, Z = 4, Dcalc = 1.689 Mg/m3, µ = 1.484 mm-1. The diffraction intensities were collected by ω scans (2.4 to 27.0°). A total of 9750/3798 reflections were collected (-

-14< =k< =14, -15< =l< =11). The structure was solved using direct methods and g the full-m t-square meth s2 using the SHELXTL [9] software l non-H ato hydrogen ere located in a urier map a ere fixed geom d treated as r on the parent C

C-H distances = 0.97 Å.

ial Activity Tcrobial activities of the ligand and com e assayed by ethod [10]

m-positive bacteria, Gram-negativef Staphylococcus aureus and Bacill subtilis and the Gram-negative bacteria, which

consist of Escherichia coli. The ligand and complexes were dissolved in DMSO and concentration of in triplicate pl mg/mL was employed as

Results and discussion

CBS, (1)] was synthesized by the tion reaction of e in 1: 2 l (Scheme 1). Five new

ydrazide-bis(s n synthesized by direct reaction of the ap organotin(IV) esence of a base

cheme 2). All the cases, a base is added to the reaction mixture in order to force the deprotonation of the li

p

ed from the setting angles of 25-cent

16< =h< =16,refined usin atrix leas od on F obpackage. Al ms were anisotropically refined. The atoms wdifference Fo nd then w etrically an iding atomatoms, with Antimicrob est The antimi plexes wer

acteria and fungi. Theplate diffusion m

Gram-positive bacteria against Graonsisting o

bc us

3 mg/mL and 5 mg/mL were tested ates. Chloramphenicol at 3control.

The carbohydrazone ligand [H4

licylaldehydcondensa

carbohydrazide with sa ratio in absolute ethanoorganotin(IV) complexes of carboh alicylaldehyde) ligand (1) have bee

propriate halide(s) with the ligand in the pr(S

gand. The low molar conductance values (10-40 ohm-1cm2 mol-1) (see Table 1) indicating non-electrolytic nature for all the organotin(IV) complexes [11].
RnSnCl4-n + Ligand [H4CBS, (1)] + 2KOH
274

275

275

H

O

NN NC C

C

OH

O

N

Sn

R R

H

H

NNC

OH

HH

Scheme 2

Table 1. Molar conductance values for organotin(IV

Compound Mola[Me2Sn(H2CBS)] (2) [Bu2Sn(H2CBS)] (3) [Ph2Sn(H2CBS)] (4)

R = M

MeOH

R = Me, Bu and Ph

abs.

[MeSnCl(H2CBS)] (5) [PhSnCl(H CBS)] (6) 2

Electronic absoption spectra The UV-Vis electronic spectra of ligand (1) and its org

teCarbohbands w

343 nmThe hig

lvin

room mperature in DMF (10-4 M) solutions over ydrazone ligand (1) exhibited three main bands ere attributed to benzene π – π* and imino (C=N

the chelation. The third band is assigned to n – π* transi and at 396-399 nm regions showed the metal-lh wavelength bands in the region 396-399 nm c

invo g the tin atom [12].

OR

O

NC

CO

N

Sn

R Cl

H

) complexes of ligand (1)

r conductance, Λm (ohm-1 cm 2 mol -1) 10 23 29

e and Ph

40 35

anotin(IV) complexes (2-6) were measured at

ected by

to charge transfer transition

200 – 800 nm range are given in Table 2. at 262, 292 and 328 nm. The first and second ) π – π* transition, which were not aff

tion. The appearance of two new bands at 266-igand coordination in all the complexes (2-6). an be assigned due

276

Tabl . The λmax (nm) peaks of ligand (1) and its organotin(IV) complexes (2-6).

Compounds λmax (nm)

e 2

(1) H4CBS 328, 292, 262

(2) [Me2Sn(H2CBS)] 398, 343, 266

(3) [Bu2Sn(H2CBS)] 398, 342, 266

(4) [Ph2Sn(H2CBS)] 396, 340, 267

(5) [MeSnCl(H2CBS)] 398, 341, 267

(6) [PhSnCl(H2CBS)] 399, 340, 268

Infrared

n.

ls

de -1

mapparen

zi

in

all the cThe me n the IR spectra of all the complexes (2-6) are attributable to the ν(Sn–C), ν(Sn–O) and ν(Sn–N) vibration bands

1H NMR The 1H NMR data for the ligand (1) and its all complexes (2-6) are presented in the experimental section. The 1H NMR spectrum of ligand (1) is characterized by four signals at 10.86, 8.44, 7.69 and 6.62–7.27 ppm, which are assigned to the protons associated with –OH, –N=CH, –CONH and aromatic ring protons, respectively. In 1H NMR spectra of organotin(IV) complexes (2-6), azomethine N=CH signal is splited into two signals at 8.14-8.17 and 8.38-8.43 ppm. This indicates that only one of the azomethine nitrogen in ligand (1) could be bonded to the Sn(IV) ion in the complexes (2-6), another one HC=N group could be free in the complexes (2-6). The disappearance of the signal due to –CONH proton in the complexes (2-6) indicated the enolization of the form of the ligand (1) in the complexes (2-6) [7]. The new signal at 10.89-11.15 ppm in the complexes (2-6) is due to the free NH group of ligand (1) which is not involved in the coordination to tin(IV) in the complexes (2-6). A signal appeared at 11.41-11.48 ppm, which is indicated that phenolic proton present in the complexes (2-6). The sharp signal attributed to methyl group attached to tin atom is appeared as a singlet at 0.68 ppm in the dimethyltin(IV) complex (2). Another sharp resonance signal attributed to methyl group attached to tin(IV) atom is appeared as a singlet at 1.14 ppm in methyltin(IV) complex (5). In the complex (3), a multiplet in the region 0.79-1.64 ppm is assigned to the butyl group attached to the tin(IV) atom Complexes (4 and 6) showed a multiplet in the region 6.70-7.62 ppm, which may be assigned to aromatic ring protons and Sn-Ph protons, respectively. The signals could not properly assigned due to overlap of corresponding signals of Ph-Sn and aromatic ring protons.

spectra The IR data for the ligand (1) and its all organotin(IV) complexes (2-6) are described in the synthesis

The IR spectra of the complexes (2-6), the disappearance of the ν(C=Osectio ) band indicating enolization of the amide group into C-OH enolic form through the amide-imidol tautomerism process

o indicating deprotonation of the funand a ctional group during coordination to tin atom [13]. The ν(C=N) band in the complexes (2-6) appeared as a strong band in the region 1600–1610 cm-1, is

rably shifted towards lower frequencies with respect to that of the free ligand (162consi 0 cm ), confir ing the coordination of the azomethine nitrogen to organotin(IV) moiety [13]. This is also

t from the ν(Sn–N) band at 440–472 cm-1 in the IR spectra of all the complexes (2-6). The nic stretching ν(N–N) band observed at 950 cm-1 for the ligand (1) is shifted in the highhydra er

region at 952–962 cm-1 in the complexes (2-6) further supporting that azomethine nitrogen is ated to Sn(IV) ion [12]. The high intensity band observed at 1272 cm-1 in the ligand (coord 1)

attributed due to phenolic ν(C–O), appears as a medium band at 1319-1340 cm-1 in the IR spectra of omplexes (2-6). These observations favour the formation of Sn–O bond via deprotonation.

dium and weak bands observed at 590-651, 520–560 and 440–472 cm-1 i

respectively, indicating coordination of the free ligand to the central Sn(IV) atom via deprotonated enolic oxygen and azomethine nitrogen in the complexes (2-6).

spectra

276

277

Cr The molecular structure along with atom numbering scheme for [Me Sn(H CBS)] (2) is shown in Figure 1 (2) are summarized in Table 3. The selected bond distances and angles for the molecules [Me2Sn(H2CBS)] (2) are given in Table 4. The 2CBS)] (2) confirm that the carbohydrazone ligand, [H4CBS, (1)] behaves as a tridentate dibasic coordinating agent via azomethine nitrogen, one enolic oxygen and one phenolic oxygen atoms and elimination of two

gen atoms are compressed to

lex [Me2Sn(H2CBS)] (2).

Form 17H18N4O3Sn

ystal structure of [Me2Sn(H2CBS)] (2)

2 2. The crystal data and structure refinement for compound [Me2Sn(H2CBS)]

X-ray structural investigations of [Me2Sn(H

potassium chloride. The two methyl groups and azomethine nitrogen atom of ligand take the equatorial positions, while enolic and phenolic oxygen atoms are in the axial position [O(1)–Sn(1)–O(2) 153.12(8)º]. The ligand forms six- and five-membered chelate rings. The ligand is not completely planar in [Me2Sn(H2CBS)] (2) and a distorted trigonal–bipyramidal geometry around the tin centre is found. The angles subtended at tin(IV) by two oxy153.12(8)º [O(1)-Sn(1)-O(2)]. The bite angles O(1)–Sn(1)–N(1) [83.58(8)º] and O(2)-Sn(1)-N(1) [72.61(7)º] are also compressed from 90º. These distortions arises from the rigidity of chelate rings, compounded by the large tin(IV) covalent radius. These bit angles are comparable to those reported for other diorganotin(IV) complexes containing both five- and six–membered chelate rings with oxygen and nitrogen donor atoms [14].

able 3. Crystal data and the structure refinement for the compT

ula CFormula weight 445.04 Crystal system Monoclinic Space group P2(1)/c Z 4 a (Å) 13.163(3) b (Å) 11.143(2) c (Å) 12.203(2) α (°) 90 β (°) 102.064(3) γ (°) 90 V (Å3) 1750.4(6) Dcalc (mg m ) 1.68-3 9 Absorption coefficient (mm-1) 1.484 Temperature (K) 273(2) Wavelength (Å) 0.71073 Final R indices [I>2sigma(I)] R1 = 0.0275, wR2 = 0.0643 R indices (all data) R1 = 0.0327, wR2 = 0.0670 Goodness-of-fit on F^2 1.095

277

278

Figure 1. Molecular structure of [Me2Sn(H2CBS)] (2). Thermal ellipsoids at the 50% level.

Table 4. Selected bond leng lex [Me2Sn(H2CBS)] (2).

ond lengths

ths (Å) and angles (°) of dimethyltin(IV) comp BSn(1)-O(1) 2.077(2) Sn(1)-N(1) 2.176(2) Sn(1)-O(2) 2.164(19) Sn(1)-C(16) 2.096(3) Sn(1)-C(17) 2.111(3) O(1)-C(1) 1.324(3) O(2)-C(8) 1.271(3) N(1)-C(7) 1.293(3) N(1)-N(2) 1.389(3) N(2)-C(8) 1.321(3) N(3)-N(4) 1.364(3) N(3)-C(8) 1.366(3) C(6)-C(7) 1.441(4) N(4)-C(9) 1.278(3) C(10)-C(9) 1.444(4) Bond angles O(1)-Sn(1)-C(16) 94.19(10) O(1)-Sn(1)-C(17) 101.90(11) C(16)-Sn(1)-C(17) 127.26(13) O(1)-Sn(1)-O(2) 153.12(8) C(16)-Sn(1)-O(2) 90.10(10) C(17)-Sn(1)-O(2) 96.43(11) O(1)-Sn(1)-N(1) 83.58(8) C(16)-Sn(1)-N(1) 126.21(10) C(17)-Sn(1)-N(1) 105.46(11) O(2)-Sn(1)-N(1) 72.61(7) C(1)-O(1)-Sn(1) 128.80(17) C(8)-O(2)-Sn(1) 113.57(16) C(7)-N(1)-N(2) 116.2(3) C(9)-N(4)-N(3) 117.7(2) C(7)-N(1)-Sn(1) 126.23(17) N(2)-N(1)-Sn(1) 117.20(15) O(1)-C(1)-C(6) 122.3(2) C(1)-C(6)-C(7) 124.3(2) N(1)-C(7)-C(6) 126.3(2) O(2)-C(8)-N(2) 126.8(2)

The asymmetry of ligand [H4CBS, (1)] is strongly reflected in the Sn-O distances. In the complex [Me2Sn(H2CBS)] (2), the Sn(1)-O(1) bond, 2.077(2) Å, is shorter than the Sn(1)-O(2) bond, 2.164(19) Å. This is due to O(2) being a carbonyl and O(1) being bound to a benzene ring. It is worth noting that in complex [Me2Sn(H2CBS)] (2) the Sn-N bond length is a little longer (2.176 (2) Å) than those reported in analogous diorganotin(IV) complex (2.146(6) Å) [15], but shorter than that of [Me2Sn(2-OC6H4CH=NC6H4COO)] (2.230(5) Å) [16] and is considerably less than the sum of the van der Waals radii of tin and nitrogen atom, 3.75 Å [17]. Due to the involvement of N(1) atom in tin binding, the bond length of N(1)-C(7) is significantly increased to 1.293(3) Å as compared with the imine function N(4)-C(9) (1.278(3) Å) which is having a double bond character. The Sn-C (methyl)

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bond lengths [2.096(3) Å and 2.111(3) Å] compare well with the reported values for diorganotin(IV) complexes derived from ONO donor tridentate Schiff bases [18]. Antimicrobial activity of the ligand (1) and its organotin(IV) complexes (2-4) Table 5 below shows the antibacterial activity of the ligand (1) and organotin(IV) complexes (2-4) tudied.

Table 5. Antibacterial activity of carbohydrazide-bis(salicylaldehyde) ligand (1) and its organotin(IV)

complexes (2-4) Diameter of inhibition zone (mm)

Bacteria H4CBS (1) [Me2Sn(H2CBS)] (2) [Bu2Sn(H2CBS)] (3) [Ph2Sn(H2CBS)] (4)

s

E. coli 10 15 20 16 B. subtilis 12 17 22 19

Stap. aureus 14 20 25 23 The preliminary screening showed that the ligand is less active compared to the organotin(IV) complexes (2-4), which indicates metallation increases activity. Other biological studies on these

nthesis and physical properties of a new series of organotin(IV) compounds with carbohydrazone ligand (1) have been described. The ligand behaved as a tridentate dinegative fashion towards to tin(IV). The complexes (2-6) are monometallic. The coordination around the tin(IV) ion is established by means of single crystal X-ray diffraction analysis on [Me2Sn(H2CBS)] (2). Acknowledgement The authors are very grateful to Universiti Malaysia Sarawak (UNIMAS), for the financial support (Grant # -01(101)/453/2004(190). The author also would like to thank the School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia (UKM), for the CHN analyses and also X-ray single crystal determination. We would also like to thank the Ibnu Sina Institute, UTM, for the help in obtaining the 1H NMR spectra. References [1] M. V., Siddalingaiah, A. H. M. (2000) “Studies on some lanthanides(III) complexes of o-, m- and p- chloro substituted diphenylcarbazones” Ind. J. Chem. 39A. 1150- 1156. [2] Wang, C. X., Du, S. X., Li, Y. H., Wu, Y. J. (2005) “A novel 3D cadmium coordination

complex [Cd(H2L) · 1.5H2O]n with strong photoluminescent property: (H4L = N,N′-bis(4-pyri .

[3] Niasari, M. S., Mostafa, R. A. (2004) “Template condensation reactions of formaldehyde with amines and 2, 3- butanedihydrazone: preparation and properties of nickel(II) complexes of

mbered decaaza macrocycles” Polyhedron 203. 1325-1331 [4] Warad, D. U., Satish, C. D., Kulkarru, V. H. (2000) “Synthesis, structure and reactivity of

compounds are still under investigations. Conclusions

The sy

Swamy, H.

dylcarboxyl)-2,6-pyridine dicarbohydrazide) ” Inorg. Chem. Comm. 8. 379-381

18-me

Zn(II), V(II), Co(II), Ni(II) and Cu(II) complexes derived from carbohydrazide Schiff base ligands” Ind. J. Chem. 39A. 415-420. [5] Tergioglu, N., Gurso, N. (2003) “Synthesis and anticancer evaluation of some new hydrazone

derivatives of 2,6-dimethylimidazo[2,1-b][1,3,4]thiadiazole-5-carbohydrazide” Euro. J. Med. Chem. 38. 781-786.

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[6] Affan, M. A., Fasihuddin,B. A., Ramli, B. H. Mustaffa, B. S., Bohari, M. Y. (2003) “In: hemistry” eds. B. A. Zaini, B. A. Fasihuddin, B. J. Ismail, S. Lau, and M.

Murtedza, Published by UNIMAS & ANALIS, Sarawak, Malaysia. 214-221.

) ions with hydrazones and azines” PhD Thesis, Universiti Teknologi Malaysia. [8] Armarego, W. L. F., Perrin, D. D. (1998) “Purification of Laboratory Chemicals” 4th edition,

rworth Heinemann, Oxford, USA. ] Sheldrick, G. M. (1997) “SHELXTL V5.1. Software Reference Manual. Bruker AXS” Inc.,

[10] Tarafder, M. T. H., Jin, K. T., Krouse, K. A., Ali, A. M., Yamin, B. M., fun, H. K. (2002)

he X-

[11] characterization of coordination compound” Coord. Chem. Rev. 7. 81-122.

[12] Khalil, T. E., Labib, L., Iskandar, M. F. (1994) “Organotin(IV) complex with tridentate

[13]

[14] dducts of

[15] ynthesis and structural characterization of diorganotin(IV) esters of salicylidene-amino acids” J. Organomet. Chem. 689. 2480-2485.

[16] Dey, D. K., Saha, M. K., Gielen, M., Kemmer, M., Biesemans, M., Willem, R., Gramlich, V. and Mitra, S. (1999) “Synthesis, spectroscopy and structure of [N-(2-carboxyphenyl) salicylideneiminato]dimethyltin(IV)” J. Organomet. Chem. 590. 88-92.

[17] Ma. C., Jiang, Q. and Zhang, R. (2004) “Synthesis, characterization and crystal structures of new organotin complexes with 2-mercapto-6-nitrobenzothiazole” Polyhedron 23. 779-786.

[18] Goh, N. K. and Khoo, L. E. (1993) “Synthesis of structural characterization of dimeric diorganotin(IV) N-2-hydroxynaphthalidene-β-amino acid complexes: x-ray structure of [Me2Sn(OC10H6CH=NCH2CH2COO)]2” Polyhedron 12(8). 925-930.

Analytical C

[7] Affan, M. A. (1999) “Novel complexes of molybdenum carbonyls, organotin(IV) and lanthanide(III

Butte[9

Madison, WI, USA.

“Synthesis and Characterization of Cu(II), Ni(II) and Zn(II) metal complexes of bidentate NS isomer Schiff bases derived from S-methyldithiocarbazate (SMDTC): bioactivity of the bidentate NS isomeric Schiff bases, some of their Cu(II), Ni(II) Zn(II) complexes and tray structure of the bis[S-methyl-B-N-(2-furylmethyl)methylenedithiocarbazato] Zinc(II) complex” polyhedron 21. 2547-2554. Geary, W. G. (1971) “The use of conductivity measurement in organic solvent for the

ligand” Polyhedron 13. 2569-2578. Casas, J. S., Sanchez, A., Sordo, J., Lopez, V. A., Castellano, E. E. (1994) “Diorganotin(IV) derivatives of salicylaldehyde thiosemicarbazone” Inorg. Chim. Acta 216. 169-172. Khoo, L. E., Xu, Y., Goh, N. K., Chia, L. S. and Koh, L. L. (1997) “Molecular adiorganotin dichloride with N- (2-oxidoarylideneaminoacidato) diorganotin(IV) complexes. Crystal structure of [Ph2Sn(2-OC10H6Ch=NCH2COO)]SnPh2Cl2” Polyhedron 16. 573-576. Yin, H. D., Wang, Q. B. and Xue, S. C. (2004) “S

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B OXIDATION OF n-B C ANHYDRIDE

Y.H. Taufiq-Yap*, Chee Keong Goh, Irmawati Ramli and Mohd Zobir Hussein

Department of Chemistry, Universiti Putra Malaysia,

i-Fe DOPED VANADIUM PHOSPHATE (VPO) CATALYSTS FOR THE SELECTIVEUTANE TO MALEI

43400 UPM Serdang, Selangor D.E., Malaysia. Email: [email protected]

Abscata sts were also found increased the amount of oxygen removed at higher temperature in H2-TPR analysis. So, the Bi-Fe doped

talysts significantly decreased the n-butane conversion. However, the Bi-Fe doped catalysts increased the selectivity of aleic anhydride due to an increase of V5+ phase and surface acidity of the catalysts.

tactic transformation of vanadyl hemihydrate precursor, VOHPO4·½H2O [2, 3]. The activation of the

For the preparation of doped precursors, the VOPO ·2H O (4.0 g) and the desire quantity of rate,

i(NO3)3·5H2O from Sigma (Bi/V = 1, 2 and 3%) were suspended by rapid stirring into isobutanol (80 3 mixtures were refluxed for 21 h with continuous stirring. Then, the blue solids

by filtration, washed and dried in an oven at 383 K for 16 h. The undoped precursor

tract. In this study, the Bi-Fe doped catalysts were found decreased the crystallite structure and surface area of the lysts. Furthermore, the Bi-Fe doped catalysts promoted the formation of αII -VOPO4 phase. The Bi-Fe doped cataly

cam Abstrak. Dalam kajian ini, mangkin dop Bi-Fe didapati mengurangkan struktur kristal dan luas permukaan mangkin. Tambahan pula, mangkin dop Bi-Fe menggalakkan penghasilan fasa αII -VOPO4. Mangkin dop Bi-Fe juga didapati menambahkan amaun pengeluaran oksigen pada suhu yang lebih tinggi. Maka, mangkin dop Bi-Fe telah mengurangkan penukaran n-butana. Walaubagaimanapun, mangkin dop Bi-Fe telah meningkatkan selektiviti maleik anhydrida disebabkan oleh penambahan fasa V5+ dan keasidan di permukaan mangkin. Keywords: vanadium phosphate, Bi-Fe, butane oxidation, maleic anhydride Introduction Vanadium phosphate catalysts are well known for the oxidation of n-butane to maleic anhydride (MA) [1]. (VO)2P2O7 is claimed to be the active phase of the catalyst which obtained by topo

vanadyl hemihydrate precursor, under the n-butane/air stream, proceeded in two parallel routes, either a reoxidation to VOPO4 phases or direct dehydration to (VO)2P2O7. This is followed by a reduction of the residual VOPO4 phases to (VO)2P2O7 [4]. The beneficial of catalysts performances were associated with a (VO)2P2O7 structure in which phosphorus atoms were associated with V4+ in a crystalline matrix and with V4+ in a disordered matrix together with V5+, implying the importance of V5+/V4+ dimeric species in the (VO)2P2O7 structure [2, 5-7]. In order that the V5+/V4+ balance is importance in controlling the catalytic performance of n-butane oxidation to MA, thus the addition of small amount Bi-Fe as dopants can influence this balance. Experimental

4 2Fe(NO3)3·9H2O (from Hamburg Chemical) (Fe/V = 1, 2 and 3%) as well as bismuth nitBcm from BDH). The were recoveredwas prepared in the same method abovementioned, but without adding Bi and Fe. The resulting undoped and doped precursors above were then undergone calcination in a flow of n-butane/air mixture (0.75 % n-butane in air) for 75 h at 673 K to generate the active catalysts. The prepared catalysts were characterised by using a Shimadzu Diffractometer model XRD-6000 for X-ray diffraction (XRD) analyses, a ThermoFinnigan Sorptomatic 1990 for B.E.T. surface area measurements, and a ThermoFinnigan TPDRO 1100 for temperature-programmed reduction in hydrogen (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD). The oxidation of n-butane was carried out in a microreactor with a standard mass of catalyst (250 mg) with online gas chromatography, as shown in Figure 1.

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Figure 1. Schematic diagram of the plug flow reactor.

Results and Discussion The introduction of Bi-Fe into VPD system had reduced the surface area from 16.1 m2 g-1 (undoped)

13.7 m2 g-1 for VPDBi1Fe1 and 12.0 m2 g-1 for VPDBi1Fe2. However, the VPDBi2Fe1 has slightly igher surface area of 17.6 m2 g-1. Chemical analysis using ICP showed that the addition of Bi-Fe into

VPD system increased the phosphorus contents of the catalysts with P/V atomic ratio of 1.00 (undoped) to 1.15. Chemical analysis also confirmed the presence of Bi and Fe with Bi/V and Fe/V atomic ratios which is similar to the calculated value, suggesting that the homogeneous existence of Bi-Fe promoters into the VPD system. Bi-Fe was found to increase the average oxidation number from 4.21 to 4.56 due to an increment of V5+ oxidation state from 21 to ~55%. The XRD patterns of all undoped and Bi-Fe doped catalysts (Figure 2) show only the characteristic reflection of vanadyl pyrophosphate, (VO)2P2O7. However, the addition of Bi-Fe into VPD lattice promoted the formation of αII-VOPO4 phase (2θ = 29.2˚), which is identified according to [8]. Besides, the Bi-Fe doped catalysts reduced the crystallite structure of (VO)2P2O7. The H2-TPR experiments were used to investigate effect of Bi-Fe on the reducibility of the catalysts, as shown in Figure 3. The undoped catalyst gave a characteristic of two reduction peaks at the region from 400-1100 K. These peaks occurred at 779 and 990 K. The first peak associated to the reduction of V5+ phase whereas the latter peak is assigned to the removal of lattice oxygen from V4+ phase. The amount of oxygen removed from both peaks is 3.85 x 1020 and 1.20 x 1021 atom g-1, respectively. The ratio of V5+/V4+ is about 0.32. However, the Bi-Fe doped catalysts show a different patterns with the first reduction peak appeared as major peak whereas the size of second reduction peak decreased remarkably. The first peak shifted to a higher temperature whereas the latter peak exhibited at lower temperature compared to the undoped material. This observation indicated that the amount of oxygen related to V5+ significantly increased to 1.49 x 1021, 1.45 21 d 1.24 x 1021 atom g-1 for VPDBi1Fe1, VPDBi1 Th

red ced to The V5+/V4+ ratio for Bi-Fe doped VPO catalysts increased to 3.25,

3.67 and 2.23 for VPDBi1Fe1, VPDBi1Fe2 and VPDBi2Fe1, respectively. A suitable V5+/V4+ ratio around 0.25 is suggested by [9] for the best cata st activity. The high amount of V5+ in the Bi-Fe doped catalysts significantly reduced the n-butane conversion and induced the MA selectivity. The addition of Bi-Fe into VPD matrix also doubled the amount acid site from 7.77 x 1020 atom g-1 (undoped) to 1.68 x 1021 atom g-1. Figure 4 shows the catalytic performance of undoped and Bi-Fe

toh

x 10 ane mount Fe2 and VPDBi2Fe1, respectively. a for oxygen removed for the second reduction

peak, which assigned to the reduction of V4+ u 4.59 x 1020, 3.95 x 1020 and 5.57 x 1020 atom g-1 for the three doped catalysts.

ly

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283

doped catalysts at reaction temperature of 673 K and gas hourly space velocity (GHSV) of 2400 h-1. The n-butane conversion -46% compared to 83%

und er erious of the catalytic performance of Bi-Fe doped catalysts is due poor cry llite of ( u rge V5+ phase. However, e Bi-Fe ed catalysts increased selec com of

existence o αII-VOPO r a .

Figu XRD pat Fi ndoped VPD and Bi-F doped catalysts. and Bi-Fe doped catalysts.

ased the ratio of V /V , hich is beyond to the optimal ratio. Hence, the n-butane conversion for Bi-Fe doped catalysts shown

crease of MA selectivity for Bi-Fe doped catalysts.

for Bi-Fe doped catalysts shown to be reduced to 32for the oped mat ial. The deletto sta VO)2P2O7, lower s rface area and la excess amount of th dop tivity to MA as pared to undoped catalyst because

f 4 phase and highe mount acid sites

re 2. terns of undoped VPD gure 3. H2-TPR spectra of u e

Figure 4. Catalysts performance of vanadium phosphate (VPO) for the oxidation of n-butane.

Conclusions Doping with Bi-Fe decreased the crystallite structure of (VO)2P2O7 phase as well as the surface area of the catalysts. Furthermore, the Bi-Fe doped catalysts significantly incre 5+ 4+

wto be significantly reduced. However, the formation of αII-VOPO4 and higher amount of acid sites led to an in

0

500

1000

1500

2000

2500

30 40 50 60

∇ (VO)2P2O7 ♦ αII−VOPO4

∇

∇∇

∇♦

∇∇

VPDBi2Fe1

VPDBi1Fe2

VPDBi1Fe1

10 20

VPD

2θ

Inte

nsity

/ a.

u.

/ degree

0

10

20

30

VPD VPDBi1Fe1 VPDBi1Fe2 VPDBi2Fe1

Sample

Per 40

80

90

c

50

60

enta

ge (%

)

70

Butane conversion MA selectivity

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Acknowledgement

. Abon, M., Bere, K., Tuel, A. and Delichere, P. (1995) "Evolution of a VPO Catalyst in n-Butane Oxidation Reaction during the Activation Time" J. Catal. 156. 28-36. Shen, S., Zhou, J., Zhang, F., Zhou, L. and Li, R. (2002) "Effect of Ce-Fe oxides additives on performance of VPO catalyst for n-butane oxidation to maleic anhydride in the absence of gas-phase oxygen" Catalysis Today 74. 37-43.

6. Granados, M. L., Conesa, J. C. and Fernandez-Garcia, M. (1993) "Physicochemical Study of Structural Disorder in Vanadyl Pyrophosphate" J. Catal. 141. 671-687.

7. Sananes, M. T., Tuel, A., Hutchings, G. J. and Volta, J. C. (1997) "The V4+/V5+ balance as a criterion of selection of vanadium phosphorus oxide catalysts for n-butane oxidation to maleic anhydride: A proposal to explain the role of Co and Fe dopants" J. Catal. 166. 388-392.

8. Abdelouahab, F. B., Olier, R., Guilhaume, N., Lefebvre, F. and Volta, J. C. (1992) "A study by in situ Laser Raman Spectroscopy of VPO catalysts for n-butane oxidation to maleic anhydride. 1. Preparation and characterization of pure reference phases" J. Catal. 134. 151-167.

9. Aït-Lachgar, K., Abon, M. and Volta, J. C. (1997) "Selective oxidation of n-butane to maleic anhydride on vanadyl pyrophosphate" J. Catal. 171. 383-390.

Financial assistance from Malaysian Ministry of Science, Technology and Innovation is gratefully acknowledged. References 1. Centi, G. (1993) "Vanadyl pyrophosphate- a critical overview" Catal. Today 16. 5-26. 2. Centi, G., Trifiro, F., Ebner, J. R. and Franchetti, V. M. (1988) "Mechanistic aspects of maleic anhydride synthesis

from C4 hydrocarbons over phosphorus vanadium oxide" Chem. Rev. 88. 55-80. 3. Hodnett, B. K. (1985) "Vanadium-phosphorus oxide catalysts for the selective oxidation of C4 hydrocarbons to

maleic anhydride" Catal. Rev. -Sci. Eng. 27. 373-424. 4

5.

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POLYCYLIC AROMATIC HYDROCARBONS IN URBAN SOILS OF KEMAMAN, TERENGGANU

Norhayati Mohd Tahir*1, Lee Boon Jeen1, Hasra Masrifah Abd. Rahim1, Marinah Ariffin1, Suhaimi

Suratman1 and Mhd Radzi Abas2

1Department of Chemical Sciences, Faculty of Science and Technology Kolej Universiti Sains dan Teknologi Malaysia (KUSTEM), Mengabang Telipot,

21030 Kuala Terengganu, Terengganu 2Department of Chemistryt, Faculty of Science, Universiti Malaya (UM), 50603 Kuala Lumpur

e-mail: [email protected] Abstract. A study has been carried out to determine the concentration and distribution of polycyclic aromatic hydrocarbons (PAHs) in urban soils of Kemaman, Terengganu. Surface soil samples (< 500 µm) were ultrasonicated using dichloromethane as solvent and the extracts fractionated on silica-alumina column. Detection and quantification of 16 priority PAHs compounds were carried out using GC-FID. With the exception of two stations, results generally indicated that the sum of 16 priority PAHs concentration (total PAHs) in soils ranged from to 6.3 to 176 µg/kg (dry weight); the two stations which exhibited significantly higher levels of total PAHs was at the main road junction located at the heart of the commercial centre of the town (535 µg/kg) and at an industrial estate, adjacent to a sawmill (547 µg/kg). Statistical analysis suggests that there is a significant difference in total PAHs concentration (p<0.05) with sampling sites. Most common PAHs compound observed in almost all the soil samples was BgP indicating the importance of vehicular emission as a source of PAHs in these soils. In addition, contribution of biomass burning to the presence of PAHs in these soils was also observed as indicated by a positive correlation between Benzo[a]pyrene with total PAHs. Abstrak. Satu kajian bagi menentukan kepekatan dan agihan hidrokarbon polisiklik aromatic (PAH) dalam tanah di Bandar Kemanan, Terengganu telah dijalankan. Sampel tanah permukaan (<500µm) diekstrak menggunakan kaedah pengekstrakan ultrasonik dengan DCM sebagai pelarut dan hasil ekstrak dipisahkan menggunakan turus silika-alumina. Pengenalpastian dan pengkuantitian 16 sebatian PAH keutamaan dilakukan menggunakan GC-FID. Keputusan lam tanah ad dalam ingkungan 6.3µg/kg ke 176µg/ katan adalah jauh lebih nggi; satu stesen terletak di simpang jalan utama di kawasan pusat Bandar (535µg/kg) dan satu lagi terletak di awasan estet perindustrian, berhampiran kilang kayu (547µg/kg). Analisis statistik menunjukkkan bahawa

tmospheric deposition a result of long-range atmospheric transport [1-6]. In this context, knowledge on the PAHs level d its dispersion on regional and national scale alaysia, even though

studies to determine the concen ces of PAHs in soils are being reported in the literature [7,8], however, this tudies is st in the east coast states of Peninsular Malaysia. In view of th a study has been initiated to address this gap in

secara amnya menunjukkan bahawa jumlah PAH dakg (berat kering) kecuali pada dua stesen dimana kepe

alah ltikterdapat perbezaan ketara dalam kepekatan total PAH diantara stesen persampelan. Hampir semua sampel tanah mengandungi BgP dimana kehadirannya sering dikaitkan dengan sumber kenderaan bermotor manakala sumbangan daripada sumber pembakaran biojisim terhadap kandungan PAH dalam tanah juga dikenalpasti berdasarkan korelasi positif antara BaP dan total PAH. Keywords: Polycyclic aromatic hydrocarbons, urban soils, ultrasonic agitation method, vehicular emissions, Kemaman Introduction Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the global environment and soil remains as one of the most important sinks for these compounds. Due to their mutagenic and carcinogenic potentials as well as their persistence, the presence of PAHs in the environment is of great global concern. PAHs are formed from the incomplete combustion of fossil and biomass fuels. Main sources of these compounds in soil include wildfires and biomass burning for agricultural land clearing,

unicipal incinerators, vehicular emission, residential heating and through the amasan are essential. At present in M

tration, composition and possible sour type of s ill limited, particularly

is,

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286

knowledge. This paper presents the results of y to determine the concentrations, composition and possible sources of PA in soils of Chukai apital of the dist emaman, Terengganu.

Experimental Study area and sampling Chukai with a population of 45,873 density, lies on the southeast end of the Terengganu state (Figure 1.1a) and is sandwiched between the booming wn of Kerteh, Terengganu and the fast growing industrial area of Gebeng, Pahang. It acts as th er for business activities and public agencies for the fastest growing distric the state of Terengganu, largely due to the booming petroleum and related industries in Paka-Kerteh belt. Owing to ategic location, also acts as a residential town to those who work in a-Kerteh belt as w Gebeng and Ku the capital of Pahang. Soil sampling was carried out around the urban area of Chukai (Table 1 and Figure 1.1b). These sites were chosen based on tr c density, resid and industrial ies and were generally diffuse source oriented. Where possible so ples were collected ca. one metre from the roadside. Twenty sampling sites were ascertaine classified to three zones. Zone A was located in

e centre part of this town, where most of the economic activities were found with major road etwork, Zone B emphasized on residential areas whereas Zone C is located in the industrial zone of

a studHs , the c rict of K

oil toe cent

t in its str Chukai

Pak ell as antan,

affi ential activitil samd and

thnthe town. Sampling involved the collection of 20 surfacial soil samples (0-10cm) using metal spades, wrapped in pre-cleaned aluminum foil and transported to the laboratory in an icebox to minimize sample degradation. Once in the laboratory, soil samples were homogenized and sieved through a 500 µm sieve.

Figure 1.1a: Chukai Town Map Figure 1.1b : Sampling site map

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Table 1 : Longitude and latitude of the sampling site

Zone Site No Longitude Latitude Sampling Site Zone A

1 2 3 4 9 10 15 16 17 18 19 20

E 103°25’29.5’’ E 103º25’29.5’’ E 103º25’19.0’’ E 103º25’02.5’’ E 103º25’17.3’’ E 103º25’11.2’’ E 103º25’25.8’’ E 103º25’43.5’’ E 103º25’10.1’’ E 103º25’38.8’’ E 103º25’33.5’’ E 103º25’25.8’’

N 04º15’07.4’’ N 04º14’50.8’’ N 04º14’21.4’’ N 04º14’21.4’’ N 04º13’56.4’’ N 04º13’27.0’’ N 04º13’39.1’’ N 04º13’49.6’’ N 04º14’09.1’’ N 04º13’54.2’’ N 04º13’48.7’’ N 04º13’39.1’’

Jln Bakau Tinggi Sek. Men. Sultan Ismail Kemaman Jln Penghiburan Center Road Junction of Jln Da Omar Jln Da Omar Jln Kubang Lurus Bukit Jakar Jln Jakar Bus station Jln Sulaimani Jln Abd. Rahman Jln Mak Donyang

Zone B

5 6 7 8 11

E 103°24’31.7’’

E 103°23’24.4’’ E 103°23’06.0’’ E 103°24’49.6’’

N 04º14’44.8’’

N 04º14 ’’ N 04º13 ’’ N 04º13’32.6’’

Kg Gong Limau

Kompleks Quarters Pend. Kemaman Kg Mentok Jln Pengkalan Lama

E 103°25’02.5’’ N 04º14’10.2’’ Jln Air Putih ’16.0’31.7

Zone C

12 13 14

E 103°25’20.8’’ E 103°25’31.3’’ E 103°25’48.2’’

N 04º13’10.8’’ N 04º12’59.6’’ N 04º13’22.6’’

Jln Jakar (Fire Station) Jakar II Industrial Estate (electronic) Jakar I Industrial Estate (sawmills)

Analytical procedure PAHs were extracted from soils (< 500 µm fraction) with dichloromethane (DCM) as solvent using ultrasonic method. The extracts were then fractionated on partially deactivated (5%) silica-alumina columns. PAHs compounds were eluted using a combination of 20ml of 10% DCM in hexane followed by 20ml of 50% DCM in hexane [9]. Identification and quantification of the 16 priority PAHs compounds were carried out using gas chromatography fitted with flame ionization detector (GC-FID) based on the retention times compared to that of external PAHs standards. These compounds were as follows: naphthalene (NAP), acenaphtylene (ACY) (PHEN), anthracene

NT), fluoranthene (FTH), pyrene (PYR), benzo(a)anthracene (BaA), chrysene (CHR), anthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP),

ibenz(a,h)anthracene (DA), benzo(g,h,i)perylene (BgP) and indeno(1,2,3,cd)pyrene (IP). Sums of

Total organic carbon (TOC) in soils was analysed using Walkley and Black’s rapid titration method [10].

, acenaphtene (ACE), fluorene (FLU), phenanthrene (Abenzo(b)fluordthese 16 compounds were collectively known as total identified PAHs (TIP). The GC-FID operating conditions were as follows: fused silica column (30m x 0.25 mm i.d; 0.25µm filmed thickness); injection temperature was set at 290°C using a splitless mode; column temperature was programmed in the following manner: hold at 50°C for 1 min, first temperature ramp of 50 - 140°C at 5°C min-1 followed by the second temperature ramp of 140 - 290°C at 3°C min-1 and then maintained at 290°C for 13 min resulting in a total run time of 82 mins; helium was used as the carrier gas with a flow rate at 1.2ml. min-1; detector temperature was set at 300°C.

287

288

Results and Discussion

s have shown that PAHs are strongly retained by the soil matrix [11,12] The ept of soil sorption of organic contaminants implies that the sorption of hydrophobic

rganic molecules is determined by the organic carbon content of the substrate [13-14]. The organic t is considered to be a very important variable related to PAHs pollution of soils [15]. In e soils exhibited rather low organic carbon content with values ranging from 0.09% to

3% w

porta

Soil Organic Carbon (SOC) Numerous studie

artitioning concpomatter contenthis study, th0.5 ith a mean of 0.27% (Table 2 and Fig. 2). A regression analysis (Fig. 3) showed a negative and weak relationship between the concentrations of the TIP and the amounts of soil organic carbon (SOC, %). Because of the very low SOC in soils, it is probable that this parameter does not play an im nt role in influencing the concentration of TIP in these soils.

0.6

0.5

0.4

%

0.2

0.3

0

0.1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Stations

Figure 2: Distribution of SOC in soil samples

Correlation between TIP and SOC%

y = -473.25x + 255.11R2 = 0.1734

200

300

TIP

(ug/

100

00 0.1 0.2 0.3 0.4 0.5 0.6

SOC%

400

500

600

kg)

Figure 3: Correlation between TIP and SOC

Total identified Polycyclic Aromatic Hydrocarbon ( TIP) The distribution of TIP obtained in this study is shown in Figure 4. With the exception of two stations (Stations 4 and 14) which exhibited significantly higher TIP than the other remaining stations, the range of TIP values found in this study was between 6.27 µg/kg to 176.3 µg/kg (Table 2); the mean concentration of TIP values obtained for the 20 sites was 129.7 µg/kg whilst the median was 101.4 µg/kg.

tice v

µg/kg) [16] but within similar range to those reported in soils of Kuala Lumpur [7, 17] and Kuala Terengganu [8]. Comparison between the three sampling zones showed that TIP values in Zone A ranged

Statis al analysis showed significant differences (p<0.05) of TIP values between the stations monitored. Thes alues are generally in great excess of the reported natural concentration of PAHs in soil (1-10

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289

fr B ranged 43.66µg/kg to 1 of 44.62µg/kg and Zone C ranging from 71.13µg/kg to 547.3µg/kg with mean value of 219.0 µg/kg and a median of 71.13µg/kg. The stations which reco Zone A and Zone C, respectively and it is conceded that their values does exhibit an influence on the mean values calculated

Station 4 was located at the busiest road junctio (Zone A) whereas Station 14 is located in the icinity of a sawmill in Zone C. In addition, as ex was also observed that most of the sampling

by major roadside generally exhibited relatively higher TIP values (e.g. Stations 3, 4, 8, 9, e residential areas (Stations 5, 7, 11, 16).

om 6.27µg/kg to 534.6µg/kg with mean value of 127.2 µg/kg and a median of 106.1µg/kg, Zone76.3µg/kg with mean value of 82.08µg/kg and a median

rded exceptionally high TIP values were located in

for the respective zone, particularly in the case of Zone C where there were only three stations monitored; n in Chukai

pected, it vsites located0) than sites located in th1

0

100

200

300

400

500

600

conc

entr

atio

n (u

g/kg

)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Stations

Figure 4: Distribution of TIP in soil samples

The distribution of the 16 PAHs compounds monitored at each sampling site were found to differ with stations, with station 4 showing the presence of all compounds except the very low molecular weight PAHs (with two benzene rings), viz. NAP, ACY and ACE. In fact, NAP was absent from all stations whilst ACY and ACE were found in only few stations at rather low concentrations (< 3 µg/kg). This observation is not surprising as these compounds are generally more volatile compared to the other higher ring number PAHs [18, 19]. Almost all stations exhibited the presence of BgP, the heavy molecular weight PAHs commonly associated with vehicular emissions resulting from internal engine combustion of gasoline [20]; BgP concentration found in this study ranged from 22.08µg/kg to 126.44µg/kg with station 4 exhibiting highest BgP concentration relative to other stations. Other high molecular weight PAHs that were present in almost all stations monitored includes DA and IP. BaP, a high molecular weight PAHs generally taken as a signature of an incomplete burning of biomass or organic matter was also present but only at selected stations with station 14 exhibiting extremely high concentration of this compound (423.5 µg/kg) accounting > 70% of the PAHs recorded for this site. These observations are consistent with the fact that Station 4 is located at the busiest road junction in Chukai whilst Station 14 is located in the vicinity of a sawmill with obvious signs of wood burning activities.

Table 2 : TIP and selected parameters Site No TOC % TIP (µg/g)

1 2

0.42 0.43

19.53 19.32

289

290

3 4 5 6 7 8 9 10 11

0.47 0.12 0.23 0.39 0.41 0.53 0.21 0.18

109.2 534.6 44.47 176.3 43.66 101.4 170.4 146.8

12 13 14

0.16 0.19 0.11

71.13 38.66 547.3

15 16 17 18 19 20

0.32 0.24 0.19 0.23 0.09 0.14

6.27 49.92 130.1 157.1 80.48 102.9

0.24 44.62

Phenanthrene to antracene ratio (PHEN/ANT) has often been used to investigate possible sources of

vironment where a low ratio (PHEN/ANT < 10) is generally considered as minance of pyrolytic sources (i.e. combustion sources) over petrogenic sources

.e. oil spill) [21-24]. In this study, the PHEN/ANT ratios in soil samples of Chukai ranged from 1.2

rried out by removing the contributions of the two

ajor trunk road. The presence of a relatively weaker but positive correlation between BaP nd TIP suggests that biomass burning also contributes to the presence of PAHs in these soils. Apart

st likely that these PAHs were contributed from activities of open burning of rubbish and garden refuse by local residents [17] which are still prevalent in the east coast states

PAHs compounds in the enindicative of a predo(ito 7.5 suggesting that the PAHs compounds found in these soils were derived from pyrolytic sources. Differentiating between the two major pyrolytic source, viz. internal engine or biomass combustion require the use of other molecular markers; as indicated above, presence of BaP in the environment is generally indicative of incomplete combustion sources, in particular combustion of organic whilst the association of BgP with vehicular emission has long been established [20]. A linear correlation analysis between TIP and BaP and between TIP and BgP for the 20 stations monitored gave an r-value of 0.68 and 0.58, respectively (Figs.5 and 6) which suggest that both sources contribute to the presence of PAHs in these soils. Station 14 is interesting in that BaP contributes over 70% of the TIP observed at the station, thus to eliminate possible bias, a second linear correlation analysis was calculated between TIP and BaP and between TIP and BgP by excluding this station giving an r value of 0.44 and 0.86. Similarly, since Station 4 is suspected to have a high contribution from vehicular emission, another correlation analysis was caextreme stations; the r value obtained was 0.41 and 0.63 for correlation between TIP and BaP and between TIP and BgP, respectively. The results of the latter two correlation analyses clearly show a stronger correlation exist between BgP and TIP suggesting that vehicular emissions is the more dominant contributor to the PAHs in the soils around Chukai. The contribution from the vehicular emission is expected as samplings were conducted in an urban area with a number of stations located close to mafrom Station 14, it is mo

particularly in Terengganu and Kelantan.

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291

Correlation between TIP and BaP

y = 5.3299x + 88.71R2 = 0.1906

0

100

200

300

400

500

0 10 20 30 40 50Bap (ug/kg)

TIP

(ug/

kg)

600

Figure 5: Correlation between TIP and BaP (20 stations)

Correlation between TIP and BgP

y = 2.7365x + 58.938

500

600

R2 = 0.3322

200

300

400

TIP

(ug/

kg)

0

100

0 40 80 120 160BgP (ug/kg)

Figure 6: Correlation between TIP and BgP (20 stations)

onclusion

otal concentration of PAHs found in urban soils of Chukai, Kemaman ranged from 6.27 µg/kg to

C T547.3 µg/kg with two stations exhibiting exceptionally high TIP values. Almost all stations showed the presence of BgP, a signature PAHs compounds known to be associated with vehicular emissions resulting from gasoline combustion in engines. A strong correlation between BgP and TIP and low PHEN/ANT ratio (<10) provide further evidence for the importance of vehicular emission sources of PAHs in these soils. In addition, contribution of biomass burning to the presence of PAHs in these soils, through open burning of rubbish and garden refuse by local residents, was also observed as indicated by a positive albeit a weaker correlation between BaP with TIP relative to the correlation between BgP and TIP.

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Acknowledgement Financial supports from KUSTEM through a short term grant vote no. 54085 is kindly acknowledged. References

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2. Kim, Eun-Jung, Oh Jeong-Eun, Chang, Yoon-Seok (2003). Effects of forest fire on the level and distribution of PCDD/Fs and PAHs in soil. The Sci. Total Env., 311:177-189.

3. Lunde, G. and Bjorseth, A. (1977). Polycyclic aromatic hydrocarbons in long –range transported aerosol. Nature, 268: 518-519

4. Aanot, E., Steinnes, E. and Schmid, R. (1996). Polycyclic aromatic hydrocarbons in Norwegian forest soils: impact of long range atmospheric transport. Environmental Pollution, 92:275-280.

5. Bakker, M.I., Casado, B., Koerselman, J.W., Tolls, J and Kollofel, C. (2001) Polycyclic aromatic hydrocarbon in soil and plant samples from the vicinity of an oil refinery. Sci. Total Env., 263: 91-100

6. Simoneit, Bernd R.T. (2002). Biomass burning - a review of organic tracers for smoke from incomplete combustion. Applied Geochemistry, 17:129-162.

7. Nasr, Yousef M.J. Omar, M. Radzi Abas, Kamal Aziz Ketuly and Norhayati Mohd Tahir (2002). Concentrations of PAHs in atmospheric particles (PM-10) and roadside soil particles collected in Kuala Lumpur, Malaysia. Atmospheric Environment, 36:247-254.

8. Norhayati Mohd Tahir, Abd. Ghani Abd. Manas, Hasra Masrifah Abd Rahim, Suhaimi Suratman and Mhd Radzi Abas (2005). Distributions of polycyclic aromatic hydrocarbons in soils of Kuala Terengganu: a preliminary study. Malays. J. Analytical Sciences. In press.

9. UNEP. 1992. Reference method for marine pollution studies no.20 (IOC, IAEA). United Nation Environmental Programme.

10. Lim HK (1975). Working manual for soil analysis. Ministry of Agriculture Malaysia, Kuala Lumpur. 11. Chung N. and Alexander,M. (1998) Differences in sequestration and bioavailability of organic compounds aged in

dissimilar soils. Environ Sci Technol, 32:855–860. 12. Chung N. and Alexander M. (2002) Effect of soil properties on bioavailability and extractability of phenanthrene

and atrazine sequestered in soil. Chemosphere, 48:109–115.

2002) Origin and distribution of polycyclic aromatic hydrocarbons in . Arch Environ Contam Toxicol., 43:438–448.

23. Colombo,J.C. Pelletier,E. Brochu ,C. and Khalil,M. (1989) Determination of hydrocarbon sources using n-alkanes and polyaromatic hydrocarbon distribution indexes. Case study: Rio de La Plata Estuary, Argentina. Environ Sci Technol, 23:888–894.

24. Baumard, P., Budzinski, H. and Garrigues, P. (1998). Polycyclic aromatic hydrocarbons in sediments and mussels of the Western Mediterranean Sea. Env. Toxicol. Chem., 17(5):765-776.

13. Chiou,.T. Peters L.J. and Freed,V.H. (1979) A physical concept of soil–water equilibria for nonionic organic compounds. Science, 206:831–832.

14. Chiou, C.T. McGroddy S.E. and Kile,D.E. (1998) Partition characteristics of polycyclic aromatic hydrocarbons on soils and sediments. Environ Sci Technol, 32:264–269.

15. Boehm, P.D. Burns, W.A., Page,D.S. Bence,A.E. Mankiewicz P.J. and Brown, J.S. (2002) Total organic carbon, an important tool in an holistic approach to hydrocarbon source fingerprinting. Environ Forensics, 3:243–250.

16. Edward, N. T .J. (1987). Polycylic aromatic hydrocarbons (PAHs) in the terrestrial environment – review. J. Environmental Quality, 12:427-441.

17. Nasr, Y.M.J.O.(2001). Characterization of solvent-extractable hydrocarbons from particulates and street dust of Kuala Lumpur. MSc. Thesis. University of Malaya, Malaysia.

18. Hathairatana, G. (1999). A study on air pollution by airborne polycyclic aromatic hydrocarbons (PAHs) in Banngkok urban atmosphere. AIT Dissertation No. EV-99-1.

19. Kim-Oanth, N. T., Botz Reutergardh, L. and Dung, N. Tr. (1999). Emissions of polycyclic aromatic hydrocarbons and particulate matter from domestic combustion of selected fuels. Environ. Sci. Technol., 33:2703-2709.

20. Zheng, M., Fang, M., Wang, F. and To, K.L. (2000). Characterisation of the solvent extractable organic compounds in PM2.5 aerosols in Hong Kong. Atmospheric Environment, 34:2691-2702.

21. Yunker, M.B. Macdonald,R.W. Gpyette, D. Paton,D.W. Fowler B.R. and Sullivan D. (1999), Natural and anthropogenic inputs of hydrocarbons to the Strait of Georgia. Sci Total Environ., 225:181–209

22. Sanders, M. Sivertsen S. and Scott,G. (surficial sediments from the Savannah River

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ASSESSMENT OF NATURAL RADIOACTIVITY IN WATER AND SEDIMENT FROM AMANG (TIN TAILING) PROCESSING PONDS

Mohsen Nasirian, Ismail Bahari, Pauzi Abdullah

Faculty of science and technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selengor,

Malaysia Abstract: Gamma spectroscopy was performed to determine the concentrations of uranium-238 and thorium-232 concentrations in the environment as a consequence of amang processing. In this study 33 water samples and 26 sediment samples were collected from 7 amang processing areas. The concentrations of uranium-238 and thorium-232 were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA) . Results showed that the maximum mass and activity concentrations of uranium in water samples were 6.64 ppm and 78.53 Bq/l respectively, while in sediment samples were 69.75 mg/kg and 860.57 Bq/kg respectively. The maximum mass and activity concentrations of thorium in water samples were 1.71 ppm and 6.90 Bq/l, while in sediment samples were 157.73 mg/kg and 637.61 Bq/kg respectively. Concentrations of uranium-238 and thorium-232 in sediment samples were higher than concentrations of uranium-238 and thorium-232 in water samples, and this may be attributed to insolubility of these radionuclides in water. The con ed from ponds involved in the close water recycle system compared to those ponds involved in the open water system. Results also showed that the concentrations of these radionuclides were higher than background indicating that amang processing activity has enhanced the natural radionuclides contents in water and sediment. Keywords: Amang processing, natural radionuclides, uranium-238, Thorium-232, gamma spectrometry Introduction: Tin mining has been a major activity of Malaysia since 1848. Up till 1980, Malaysia contributed 30.7 % of the world’s produce of tin. However her contribution to the world’s tin dropped sharply since 1983. By 1996 Malaysia’s contributed only 3.9 % and by then there were only 63 mines in operation (Malaysian Department of Mines, 1997). With the drop in tin production and the cost of world’s tin, attention shifted toward processing amang (a tin by product) for valuable minerals [1]. Amang is a local (Malaysian) slang word used by the tin mining community to describe tin tailing consisting of a mixture of tin ore, sand and minerals initially discarded by tin miners [5, 16]. Amang or by- product of tin minerals reprocessing, has been found to contain valuable minerals such as ilmenite, zircon, monazite, xenotime, columbite and struvirite that has high demand in production industry [2]. Studies done by the Atomic Energy Licensing Board have shown that the uranium and thorium concentrations vary in monazite, xenotime and ilmenite respectively [3]. Valuable minerals such as monazite ([Ce,La,Y,Th]PO4 ) are radioactive because they contain naturally occurring thorium. Zircon becomes radioactive when cations, such as Zr+4, are replaced with uranium or thorium [2, 14]. Other minerals may be conta ral occur g radioactive m nced natural occurring radioactive materials (TENORM) during the mining and amang processing activities. Amang also consists of heavy metals. The mining of tin has been blamed for upsetting the ecosystem. Beside the obvious scaring of large and beautiful landscape and turning it into barren lands, tin mining together with amang processing have also been blamed for changing concentration distribution of elements in the ecosystem, namely the distribution of heavy metals as well as NORM in soil and water [15].

centrations of both radionuclides were higher in sediments collect

minated with minerals that are radioactive. Amang consists of natuaterials (NORM) such as 238U and 232Th that are technologically enha

rin

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294

In amang processing separation and concentration of valuable minerals are based on three physical properties, i.e. different specific gravities, magnetic and electrostatic properties. In this process large volume of water is used in wet gravity separation process and has become a potential source of environmental pollution depending how the water is managed. The water may be released directly into the environment (open water management system) or recycle (close water management system). Such activities have been associated with giving rise to radiological environmental problems [16]. The risk of such problem is high due to the fact that legally, amang plants in Malaysia are categorized as small amang factory and is exempted from licensing by the Atomic Energy Licensing Board (small amang factory) Order 1994 [4]. In Malaysia, there are 113,700 hectares (281,000 acres) of former mining land and 14.4 percent of it was in the form of water pond, used extensively for aqua culture. About four percent has been turned into food production areas, when tin mining collapsed in the 1980s [6]. Using energy dispersive X-ray fluorescence (EDXRF) A.F.Oluwole [10] measured the concentrations of radionuclides and toxic heavy metals in the soil around a lead / tin smelter and also air particulate and mining wastes collected from some tin mines and a tin mill. The concentrations of thorium and uranium reported ranged between 0.01 - 2.94 % and 0.002 - 0.11% in the tailing and between 2.25 - 9.09% and 0.25 - 5.65% in the monazites respectively. Studies by Hu [12] and Kandaiya have also shown the presence of naturally occurring radionuclides in the valuable minerals of amang. Ismail B. [15, 16] reported that amang processing reduces the pH of water and radionuclides contaminates the water and consequently decrease quality of water. MaterSampling location: Seven different amang processing plants employing three kinds of water management systems (i.e. open water system, close water natural and close water man made systems) were chosen for this study. Thirty three water samples and 26 sediment samples were taken from seven amang plants. All water and sediment samples were taken from Selangor and Perak State in Malaysia. Hand made water sampler was used for taking water sample from surface level (top), mid and bottom levels of the lakes and ponds. If the depth of pond was less than three meters, only one water sample from top was taken, if the depth was more than three meter and less than four meter, two water samples from top and bottom were taken. If the depth of the lake was more than four meters, three water samples (top, middle and bottom levels) were taken. Water samples were collected and stored in extra clean polyethylene bottle. Water samples collected were labeled as SXLy , where S indicates sampling station and L indicates depth at which the water samples were collected. X represents station number from 1-18, and y represents depth of the water samples from 1-3. For example water sample S1L1 means station number 1 and top level of water. Twenty six sediment samples were collected from two different amang processing plants employing close water natural system. Sediment samples were collected in special PVC container. Sediment sampler model Ejkelkamp with PVC transparent tubes (60,100,150 cm length and 63 mm diameter) was used for taking the sediment samples. Sediment samples collected were labeled as SXLy . Where S indicates sampling station and L indicates depth at which the sediment samples were collected. Treatment of samples: The determination of uranium-238 and thorium-232 concentrations in water samples were based on 2000 ml of water samples collected and subsequently evaporated to 200 ml and stored, capped and sealed in Merinelli containers. In sediment samples, large stones and other objects were removed, then were dried in oven at 105ºC for 24 hours to constant mass, then sieved through mesh 500 µm. All sediment samples were weighted and sealed in Merinelli containers. All water and sediment samples were kept for at least four weeks before counting in order to allow the in-growth of uranium and thorium decay products and achievement of secular equilibrium for 238U and 232Th with their respective progenies.

ials and Methods

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295

Gamma spectroscopy: A stand-alone high-resolution gamma spectrometric system was used for the measurement of the energy spectrum of the emitted gamma rays in the energy range between 50 kev and 3000 kev [12]. The gamma spectroscopy system consists of the high purity germanium (HPGe) detector from Oxford Company with an efficiency of 15%. Detector model number is CNVDS30 with crystal characteristics of diameter 45.3 MM, length 47.3 mm, active volume 75 and germanium dead layer thickness 0.3 microns and detector to window distance less than or equal to 5 mm. Also end cap outside diameter is 76-mm aluminum 1 mm thick. The spectra were fed through the Amplifier Canbera model 2020 to the multi channel analyzer with two analog to digital converters and the memory containing 8192 channels. The multi channel analyzer was directly connected to a personal computer where the spectra were processed and stored. In this system bias supply is from Ortec Company. The detector is mounted on a cryostat which is dipped in to a 30 liters dewar filed liquid nitrogen. The detector is surrounded by a cylindrical shield consisting of lead with thickness of 5 cm, which provides an efficient suppression of background gamma radiation present at laboratory site. Also Soil-IAEA-375 was used as standard reference for sediment samples and uranium and thorium mix stock standard solutions were used as standard reference for water samples. Analysis and instrumentation: Gamm 2 water tivity concentration present was counted for 86400 seconds (24 hours), while sediment samples were counted for 43200 seconds (12 hours). Prior to the sample measurement, the environmental gamma background at the laboratory site was determined using a blank Merinelli under identical measurement conditions. The laboratory background reading was averaged from four readings taken. Based on the measured gamma ray photo peaks, emitted by specific radio nuclides in the thorium-232 and uranium-238 decay series, their radiological concentrations in samples collected can be determined. Calculations relied on establishment of secular equilibrium in the samples, due to the much smaller lifetime of daughter radionuclides in the decay series of thorium-232 and uranium-238. More specifically, the thorium-232 concentration was determined from the concentrations of Tl -208 in the samples, and the concentration of U-238 was determined from concentrations of the Bi-214 decay products. Energy 1120.3 kev belonging to radionuclide Bi-214 was used for measuring mass concentration and activity of uranium-238 in water samples. Energy 2614.4 kev belonging to radionuclide Tl-208 was used for measuring concentration and activity thorium-232 in water samples. Energy 609.3 kev belong to radionuclide Bi-214 was used for measuring mass concentration and activity of uranium-238 in sediment samples. Energy 2614.4 kev belonging to radionuclide Tl-208 was used for measuring mass concentration and activity concentrations of Th-232 in sediment samples. The mass and activity concentrations of radionuclides were obtained using related formula [3]. Results and discussion: Before detail discussion is made in this study, the overall finding of this study is prepared first. Figusamp ater sampling stations along a river (S17 being upstream and S18 down stream). L1, L2 and L3 are different depth where water samples were taken. L1 being near the surface and L3 being near the bottom. Figures 3 and 4 show the mass and activity concentrations of uranium and thorium respectively in sediment samples in amang plant number 1. Figures 5 and 6 show the mass and activity concentrations of uranium and thorium in sediment samples in amang plant number 2. Amang plants number 1 and 2 represent two different amang plants. S1-S4 are sediment sampling stations around the ponds, and L1-L4 are the sediment layer (L1 means top sediment layer and L4 means bottom sediment layer).

a spectroscopy was used to determine the concentrations of uranium-238 and thorium-23and sediment samples. Water sample was put into the shielded HPGe detector and the ac

in

res 1 and 2 show the mass and activity concentrations of uranium-238 and thorium-232 in water les. S1- S16 are water sampling stations in different amang ponds, S17 and S18 are w

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296

Figure 1 and 2 show the mass and activity concentrations of uranium-238 and thorium-232 in water samples resp ples was 6.64 ppm

d maximum activity concentration was 78.53 Bq/l belonging to sample taken at station 8 (ie. S8L1). Maxi y concentrations of thorium-232 in water samples were 1.71 ppm

0 Bq/l tive es s w corde atio 15 Figures 3 and 4 show the mean a ty tions o uraniu orium-232

t samples i ang t nu 1 respectively. Maximum ma ncentratio ples was 69.75 mg/kg and maximum activity conce ion was 86

adings were recorded at station 3 (ie. S3L1). Maximum mass concentration of thorium-232 in sedime mples in amang plant 1 was 157.7 g/kg and imum act concentration was 637.6 /kg, recorded at station 2 (S2L1). ures 5 and 6 show the mass and activity concentrations of uranium-238 and thorium-232 in sedi p ang plant num er 2. Maximum mass concentration of uranium-238 i ent samples w 9 m and um activity conce tion was 0 Bq/kg,

re observed in station 1 (S1L1). Also maximum of mean mass concentration of thorium in samples in amang plant 2 was 150.8 mg/kg and maximum activity concentration was 609.60

se readings were recorded at station 1 (S1L1). Table 1 shows the summary and statistical calculations of data collected from all water and sediment samples. Results in table 1 showed that the mean concentration of uranium-238 in water

was 4.34 ± 1.5 a range 0.12 - 6.64 ppm. Also results showed that the ion of thorium ples was 0.37 ± 0.37 ppm

m. Mean maximum concentrations of uranium-238 and also thorium-232 were observed in S8-L1) and station 15 (S15-L1) respectively. Both stations were close to water discharge

point of the plant. Both stations involve amang plant using the close water management system table 1 showed that the mean concentration of uranium-238 in the sediment samples in amang plant 1 was 18.00 ± 17.55 mg/kg and the range was between 6.82 - 69.75 mg/kg. The mean c tration o horiu 2 in ent samples taken from amang plant 1 was 62.05 ± 3

the range w een 26.00 – 157.73 mg/kg. Maximum n concen ns of uranlso thorium-232 were observed in stations 3 (S3-L1) and 2 (S2-L1) respectively. These two

re close to water discharge point, and where the water management in these amang plants ter system type.

also shows the statistical calculations of uranium-238 and thorium-232 in the sediment n from ama ant me tration of uran sediment samples in a

6.47 mg/kg and was in the range 4.96-27.95 m . The m32 in sediment samples in amang plant 2 was 40.49 ± 39.41 mg/kg and was in the range 50.80 mg/kg. Maximum mean concentrations of uranium-238 and also thorium-232 were

station 1 (S1-L1), i.e. discharge point in this amang plant, where the management system in this amang plant is close water system type.

Table 2 shows statistical calculations and activity concentrations of uranium-238 and thorium-232 in water collected from seven amang plants highlighting the difference water samples collected at point of discharge and those collected elsewhere. This table shows their mean ± standard error mean, median, range and standard deviation. Based on these results the highest uranium-238 and thorium-232 in all amang plants were recorded near or at the point of water discharge (except amang plant 5). The median concentrations of uranium-238 in discharge points were 56.53, 64.93, 71.55, 20.40, 64.00, 54.61and 7.62 Bq/l respectively and for thorium-232 were 1.19, 1.39, 2.55, 1.33, 1.46, 6.9 and 0.12 Bq/l respectively. It should be mentioned that near station S3 in amang plant no 5 there were several mounds and valuable minerals next to the point rainfall could have washed down these minerals and carry them into the pond.

ectively. Maximum mass concentration of uranium in water saman

mum mass and activit respecand 6.9 ly. Th e reading ere re d in st n 15 (ie. S -L1

m-238 and th).

mass nd activi concentra fin sedimenuranium-238 in sediment samBq/kg . These re

n am plan mber ss co n ofntrat 0.57

nt sa 3 m max ivity1 Bq

Figment samples sam

n sedimvalues wesediment

led at am bmaximas 27.5 g/kg ntra 340.4 these

Bq/kg. The

samplesconcentrat– 1.71 pp

8 ppm and with mean -232 in water sam and the range was between 0.01

stations 8 (

Results from

oncenmg/kg and

a

f t m-23 sedim 9.34 as betw mea tratio ium-

238 and stations weis cl se wao

Table 1samples takeplant 2 was 9.62 ±thorium-211.92 - 1

ng pl 2. The an concen ium in mang g/kg ean concentration of

observed in

296

297

297

0

1

2

3

4

5

6

7

S 1-

L1 L2

4-L

1

S 4

–L2 2

S 6-

L1

7-L

1

S 7-

L 2

S 9-

L1

S 10

-L1

S 11

-L1

S 12

-L 3

S 13

-L1 2

S 14

-L1

S 14

-L 2

S 14

-L 3

S 17

-L1

S

ncen

trat

ions

(ppm

)A

ctiv

ity c

once

ntra

tions

(Bq/

l)M

ass

co

0

10

20

30

40

50

60

70

80

90

S 1-

L1

S 1-

L2

S 2-

L1

S 2-

L2

S 3-

L1

S 3-

L2

S 4-

S 4 S 4-

S 5-

S 5

-

S 5-

S 6-

L1

S 7-

L1

S 7

-L 2

S 8-

L1

S 8

-L 2

S 9-

S 1

0

S 1

1-L1

S 1

2

S 12

-L 2

S 12

-L 3

S 1

3-L1

S 13

-L 2

S 13

-L 3

S 1

4-L1

S 14

-

S 14

-L 3

S 1

5

S 1

6

S 1

7-L1

S 18

-L1

Stations

S 1-

L2

S 2-

L1

S 2-

S 3-

L1

3-L

2S S S

4-L3

S 5-

L1

S 5-

L

S 5-

L3

S S 8-

L1

S 8-

L 2

tations

S 12

-L1

S 12

-L 2

S 13

-L

S 13

-L 3

S 15

-L1

S 16

-L1

S 18

-L1

Uranium-238 Thorium-232

3Figure 1. Mass concentrations of

L1 –L2 L3 L1 L 2 L3 L1 -L1

-L1

L 2

-L1

-L1

Uranium-238 Th -

Figure 2. Activit ations of U-238 and Th-232 in water samples

orium 232

y concentr

U-2

8 and Th-232 in water samples

298

298

0

20

60

80

120

140

160

180

S L3 S 2-L1 3-L2 S 3-L4 S 4-L1 S 4-L2 S 4-L3 S 4-L4

S

Mas

s co

ncen

trio

ns (m

g/kg

)

40

100

1-L1 S 1-L2 S 1- S 1-L4 S 2-L2 S 2-L3 S 3 –L

tations1 S S 3-L3

at


and Th-232 in sediment sample (amang plant 1) Figure 3. Mass concentrations of U-238

0

100

200

300

400

500

800

1000

S 1-L1 S 1-L2 -L3 -L1 S 2-L2 S 2-L3 S 3 –L1 S 3-L2 S 3-L3 S 3-L4 S 4-L1 S 4-L2 S 4-L3 S 4-L4

Stations

Act

ivit

con

cent

ratio

n (

q/kg

)

600

700

900

S 1 S 1-L4 S 2

yB

Uranium-238 Thoriu

Figure 4. Activity concentrations of U-238 and Th-232 in s les (amang plant 1)

m-232

ediment samp

299

160


120

140

)

80

100

trat

ions

(mg/

kg

0

20

40

60

S 1-L1 S 1-L2 S 1-L3 S2 -L1 S 2-L2 S 2-L3 S 2-L4 S 3–L1 S 3-L2 S 3-L3 S 3-L4

Stations

Mas

s co

ncen

Figure 5. Mass concentrations of U-238 and Th-232 in sediment samples (amang plant 2)


0

600

700

100

200

300

Act

ivity

con

cent

rat 400

500

ion

(Bq/

kg)

S 1-L1 S 1-L2 S 1-L3 S2 -L1 S 2-L2 S 2-L3 S 2-L4 S 3–L1 S 3-L2 S 3-L3 S 3-L4

Stations

Figure 6. Activity concentrations of U-238 and Th-232 in sediment samples (amang plant 2)

299

300

Table 1. Statistical calculations of water and sediment samples

Sample size

Mean Std error of mean 95%

Conf limit 95%

conf limit

Minimum

Media ( 50 percentile)

Maximum

Sample Lower Upper

U in Water sample

33 4.34 ppm

0.275 3.785 4.909 0.12 ppm

4.750 ppm

6.64 ppm

Th

S

(am

27.730 6.82 8.84 69.75

s

(am

mg/kg mg/kg mg/kg mg/kg

sediment Sample

(am

mg/kg 2 5.275 13.975 4.96

mg/kg 7.13

mg/kg 27.59 mg/kg

ssample

(amang plant 2)

mg/kg mg/kg mg/kg

in water sample

33 0.37 ppm

0.064 0.231 0.501 0.01 ppm

0.331 ppm

1.71 ppm

U in 15 18.00 4.533 8.285

ediment sample

mg/kg mg/kg mg/kg mg/kg

ang plant 1)

Th in 15 62.05 10.159 40.261 83.844 26.00 46.80 157.73

ediment sample

ang plant 1)

U in 11 9.62 1.95

ang plant 2)

Th in 11 40.49 mg/kg

11.882 12.024 66.970 11.920 22.57 150.80

ediment

300

301

301

Table 2. A 238 232 ecte m 7 amang plant.

ran Thorium-232

ctivit

U

y concentrations of U and Th in water coll

ium-238

d fro

ang Plants/Sample Mean ± sem

(Bq/L)

Median(Bq/

L)

Median

(Bq/L)

Range (Bq/L)

St. dev. Am Range

(Bq/L) St.

dev. Mean ±

sem (Bq/L)

Plant 1 S1-Point of discharge

56.53±9.645 56.53 1.19 0.92-1.46 3846.88-66.17

13.64

1.19±0.27 0.

S2 46.74±4.680

46.74 0.37 42.06-51.42

6.62 0.37±0.15 0.35-0.38 0.21

Plant 2

S1-Point of discharge

64.93±1.18 64.93 1.39 1.3-63.75-66.10

1.66 1.39±0.09 1.47 0.12

S2 47.64±2.05 48.11 0.51 43.88-50.92

3.54 0.532±0.6 0.43-0.63 0.10

S3 70.28±4.67 73.21 0.12 61.14-76.48

8.09 0.16±0.04 0.12-0.24 0.07

Plant 3 (pond 1)

S1-Point of discharge

71.55 71.55 2.55 2.55 00 71.55 0.00 2.55 0.

S2 60.44±3.33 60.44 1.89 1.61-2.16 39 57.11-63.77

4.71 1.89±0.28 0.

S3 71.17±7.36 71.17 0.80 0.41-1.19 0.55 63.82-78.53

10.40

0.8±0.39

Plant 3 (pond-2) 37.75 37.75 37.75 1.65 1.65 0.00 0.00 1.65

302

302

Plant 4

S1-Podischarge

20.40 int of 20.40 20.40 0.00 1.33 1.33 1.33 0.00

S2 19.521952 19.52 0.00 1.27 1.27 1.27 0.00 Plant 5

S1-Podischarge

64.00 1.int of 57.03±7.75 41.56-65.40

13.42

1.42±0.33 46 0.82-1.97 0.58

S2 1.60.866±1.52

61.31 58.04-63.25

2.63 1.50±0.10 47 1.34-1.70 0.18

S3 5.19 2.66.87±5.19 56.53-72.90

9.0 2.42±0.37 77 1.69-2.81 0.64

Plant 6

S1-Podischarge

54.61 6int of 54.61 54.61 0.00 6.9 .9 6.9 0.00

S2 34.05 34.05 34.05 0.00 6.07 6.07 6.07 0.00 Plant 7

S1-Dow 7.62 0.12 0.12 0.00 n stream 7.62± 7.62 0.00 0.12 S2-Up str 1.48 0.03 0.03 0.00 1.48 0.00 0.03 eam 1.48±

S1-S3 are sampling s Sem: Standard error St.D: Standard devia

tation mean tion

The higher uranium-238 and thorium-232 concentrations in water samples collected at down stream related to upstream, suggested that amang processing enhances their concentrations. In the case of plants employing close water system, such enhancement is expected with every recycling

rocess.

r

h n 8

m

m-238 in natural ground water. Natural uranium is the only hemical toxicity is the limiting factor in risk assessment the

aximum contaminant level for uranium is 20 µg/l [6]. As mentioned mean concentration of uranium-238 in amang water samples average concentration of uranium in amang water samples was around 220 contamination level of uranium. A.

artin Sanchez [18] reported low concentration of uranium series in water samples in Extramadura

2-120.88 mg/kg respectively. Redzuwan reported activity oncentrations of uranium-238 and thorium-232 ranging from 6.27-435.95 Bq/kg and 12.90-301.59 q/kg respectively. Our finding were in correlations with those of Ismail et al. and Redzuwan et al. in

both the

l

en from amang processing plants river and ponds where analyzed for uranium-238 and 2 concentrations. Results further confirm other earlier limited studies that amang

processing enhances NORM into TENORM. Concentrations of uranium-232 were higher in water than thorium-232.However it was the opposite in sediment. Overall uranium-238 and thorium-232 concentrations were higher in sediment than water indicating the insolubility of these NORM in water and suggesting that they remained in mineral form in the sediment.

p The enhancement of NORM in water may also be attributed to the acidity of the recycling water. Such acidity is caused by the acidic nature of amang [16]. Acid conditions caused the radionuclides to dissolved in water. Another finding from this study is that, the mean mass and activity concentrations of thorium-232in all sediment samples (amang plants no 1 and 2) were higher than the mass and activityconcentrations of uranium-238 in sediment samples (table 1). However this was the opposite in watesamples. Results from this also showed that average concentrations of uranium-238 and thorium-232 in botwater and sediment samples were higher than those measured from areas that were not involved iamang processing or tin mining activities. According to R.M.R. Almedia [6], natural uranium-23concentration in ground water range from 0.1 to 10 ppb, in this study the mean maximuconcentration in water sample reported was 6.64 ppm (in S8-L1), or 6600 times more than themaximum concentration of uraniuradioactive substance for which cm

was 4.34 ppm, it means the times more than maximum

M(Spain), ranging from 0.024 to 2.69 ppb and most of them were below 1.0 ppb. Likewise the uranium concentration of Slovenian spas area ranged from 0.2 to 2.7 ppb [Kobal, 9]. According to Boyle (1982) the mass concentration of thorium in natural water is around 0.005 – 0.5 ppb. In this study the concentration of thorium-232 in water samples ranged from 0.03 – 1.7 ppm. The maximum mean concentration of thorium-232 in water taken at station S15-L1 was 3400 times higher than those reported by Boyle in ground water. I. G. E. Ibeanu [8], showed that the measured concentration levels of uranium and thorium in tin tailing samples and the measured dose rates in Nigeria were found to be elevated with values up to approximately 100 times above background levels of control soils. Higher concentrations of uranium-238 and thorium-232 in sediment relative to water observed in this study supported other earlier reports [15, 16]. Higher concentrations of both radionuclides in sediment is attributed to the insolubility of minerals bearing radionuclide in this water, such minerals include monazite, zircon and ilmenite. Ismail et al. [15, 16] and Redzuwan et al. [2] carried out similar studies in Perak and Selangor in Malaysia respectively. Ismail et al reported uranium-238 and torium-232 mass concentrations ranging from 6.93- 11.45 mg/kg and 27.7cB

mass and activity concentration of both radionuclides and their differences between uranium-238 and thorium-232. Conclusion: Gamma ray spectrometry definitely appeared to be a useful and sensitive method for obtaining actuainformation on radionuclides in the environments. A total of 33 water samples and 26 sediment samples tak /

thorium-23

303

Acknowledgment: The authors would like to acknowledge the Atomic Energy licensing Board of Malaysia (AELB) and also the Universiti Kebangsaan Malaysia for funding this work through research grant -D-036-2002. References: 1. Ismail, B.Y., Othman, M. Soong, H. F., (2000) “Effect of tin dredging on the environmental concentrations of arsenic, chromium and radium-226 in soil and water”, J. Sains nuklear Malaysia, Vol 18, No1. 2. Redzuwan Yahaya, Ismail Bahari , Amran Ab. Majid, Muhamad Samudi Yasir, Lin Cheng lee, (2002) “The impact of amang processing activity on the water quality and sediment of open water system”, 15th Analytical chemistry symposium, Penang, Malaysia. 3. AELB. (1991) “Radiological hazards assessment at mineral processing plants in Malaysia “ Atomic energy Licensing Board of Malaysia, LEM/LST/16/pind. 1. 4. M.J. azlina, B.Ismail, M. Samudi Yasir, Syed Hakimi Sakuma, M.K. Khairuddin, (2003) ”Radiological impact assessment of radioactive minerals of amang and ilmenite on future land use using RESRAD computer code, “ J. of Applied radiation and isotopes, 58, 413-419 .

. M.J.Azlina , B.Ismail , M. Samudi Yasir , Taiman , K. (2001) ”Work activity , ra ation dosimeters and xternal dose measurement in amang processing plant, j. sains nuclear Malaysia , vol.19, no 1&2 ,31-39 .

ater radon, radium and uranium ental radioactivity, 73, p. 323-

34. J. Al-J

urine” , J

river h and evaluation of the radiation hazard”, J. Applied

0. Mohd Tadza Abdul Rahim, Shamsulbahrin Ludin , Mohd Yusof Harun , Amran Kamarudin , Abdul hamid atip , Mohd Azwar Hashim , (21-22 June,1994) ”Radiological assessment at mineral processing plants in

Malaysia “ , Radiological hazards in the tin mining and heavy mineral processing , seminar, Ipoh, Malaysia. 11. W.W.S.Yim, (Aug 1976) ”Heavy metals accumulation in estuarine sediments in a historical mining of Cornwall “ , Marine pollution Bulletin , Vol 7, issue 8, p. 147-150 . 12. Michalis Tzortzis, Haralabos Tsertos, Stelious Christofides, George Christodoulides, (2003) ”Gamma radiation measurement and dose rates in commercially – used natural tiling rocks (granites)”, J. of environmental radioactivity, 70, p. 223-235. 13. Hu, S.J., Kandaiya, (1985) “ Radium 226 and Th 232 concentration “, J. Health physics, 49, p. 1003-1007 . 14. Ismail B., Mokhtar M.B. , tan B.H., (1999), “ Impact of amang processing on the water quality of an immediate water body : A case of a recycling water system “, sci. int . ( lahore) 11(1), p 1-4. 19 15. Ismail Bahari, redzuwan Yahaya , Muhamad Samudi Yasir , Amran Ab. Majid, Lin cheng Lee, (2003) “ The impact of open water management system in amang processing on the water quality and 238U and 232Th activity concentration in sediment and water “ , J. of Biological science, 3(11), p. 1063-1069. 16. B.Ismail , M.S. Yasir, Y. Redzuwan , A.M.Amran, (2003) ”Radiological environmental risk associated with different water management system in amang processing in Malaysia“ , Pakistan j. of biological science, 6 (17), September, p. 1544-1547 . 17. D.Malczewski, L. Teper, J.Dorda, (2004) “Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdroj in Sudetes , Poland , by in situ gamma – ray spectrometry”, J. of environmental radioactivity, 73, P. 233-245. 18. A. Martin Sanchez, F. Vera Tome R. M. Orantos Quintana, V. Gomes Escobar, M. Jurado Vargas, (1995) “Gamma and alpha spectrometry for natural radioactive nuclides in the Spa waters of Extramadu ain” J. of environmental radioactivity, Vol 28, No. 2, p. 209-220.

5e

di

6. R. M.R. Alemedia, D.C. Lauria, A. C. Ferreira, O. Sracek, (2004) “ Ground wconcentrations in Regiao dos Lagos, Rio de Janerio State, Brazil”, J. of environm37. undi, E.Werner, P. Rot, V. Hollriegl, I. Wendler, P.Schramel, (2004) ”Thorium and uranium in human

. of environmental radioactivity, 71, p. 61-70. 8. I. G. E. Ibeanu, (2002) “Tin mining and processing in Nigeria: Cause for concern” , J. of environmentalradioactivity, Vol, 64, Issue 1, P.59-66. 9. Mantazul I, Chowdhury, M. N. Alam, S.K.S.hazari, (1999) ”Distribution of radio nuclides in the sediments and coastal soils of Chttagong , Bangladesradiation and isotopes, 51, P. 747-755. 1L

a-Sp

304

COATING THICKNESS MEASUREMENT FOR GOLD BY USING EDXRF

Meor Yusoff M.S., Masliana Muslimin and Fadullah Jili Forsani*

Materials Te y Division,

Malaysian Institute for Nuclear Technology Research,

Bangi, 43000 Kajang, Selangor,

ence and Technology,

UiTM, Shah Alam

e-mail: [email protected]

Abstrac

andards of different thicknesses. The calibration graph

hows a straight line for thin coating measurement until 0.9µm. Beyond this the relationship was not

linear and this may b

performed on two different samples of gold-coated jewelry and a phone connector. Result from the

phone connector analysis seems to agree w ating value. From the

a -coated j able to dif article gold

electroplated.

Abstrak

Kertas kerja ini menerangkan kajian ke atas pembangunan prosedur analisis pen ketebalan penyalutan emas dengan menggunakan teknik EDXRF. lan penyalutan pat diukur dengan menghubungkan bacaan keamatan di bawah puncak Lα bagi Au. Bagi mendapatkan kepu ang tepat, g tkan meng s salu i dari

elbagai ketebalan. Graf kalibrasi menunjukkan garis lurus bagi pengukuran penyalutan nipis iaitu 9 µm ketebalan. Melebihi nilai ini, perhubungan adalah menjadi tidak linear dan ini

ungkin disebabkan oleh kesan penyerapan tersendiri. Analisis kuantitatif juga dilakukan ke atas 2 ampel berlainan iaitu barang kemas bersalut emas dan penyambung telefon. Keputusan menunjukkan nalisis bagi nilai penyalutan emas penyambung telefon memberikan nilai yang sama dengan nilai

yang di erolehi daripada pihak pengeluar. Bagi analisis barang kemas pula didapati ianya dapat dibezakan kepada 2 jenis salutan iaitu gold wash dan gold electroplated. Keywords: EDXRF, gold, coating thickness, electroplated, gold wash

chnology Group,Industrial Technolog

*Department of Chemistry,School of Sci

t

The paper relates a study on the development of an analysis procedure for measuring the gold coating

thickness using EDXRF technique. Gold coating thickness was measured by relating the counts under

the Au Lα peak its thickness value. In order to get a reasonably accurate result, a calibration graph

was plotted using five gold-coated reference st

s

e resulted from the self-absorption effect. Quantitative analysis was also

ith the manufacturer’s gold co

nalysis of gold ewelry it had been ferentiate the two s as gold wash and

gukuran Keteba emas da

tusan y raf kalibrasi diplo guna 5 jenis ema tan rujukan piawapsehingga 0.msa

p

305

Introduction

oatings represent a variety of metallic mixtures and compound typically used to strengthen certain

features

ic,

nd

[2]. Gold filled is produced when a layer of at least 10-karat gold is permanently bonded by

heat and

ted

ss than

stems are used for the precise non-destructive measurement of

ell as for alloy coatings and in the incoming material inspection. Besides that

EDXRF also proves to be a relatively fast tec

C

of a product to make it better fit its purpose. Gold is one of the common metal used as coating

[1]. It is applied in many usages especially as imitation jewelry and its related articles. In electron

gold coating is largely used in connectors and contacts due to its high electrical conductivity,

excellent corrosion and wear resistant. Electrical connectors are used in a wide range of equipment

such as computers, phones and cars. Measuring the coating thickness of a coated product is an

important quality control procedure. Manufacturers need an excellent quality control of coatings

during their entire processes in order to avoid production loss, waste of coating material and achieve

fastest possible control over their process. Car manufacturers for example need to quickly analyze

different coating weights in order to keep quality at highest standards.

Gold-coated articles can be classified as gold filled, rolled gold plate, gold electroplate a

gold wash

pressure to one of more surfaces of a supporting metal. These coatings are used as watch

casings, cigarette casings, high fashion jewelry, and numerous other decorative items. Gold-coa

articles can also be produced by mechanically bonding on to a base metal. This technique is called

rolled gold plate. Another technique that is widely used in the industry is by electrolysis. Here, a gold

electroplate is perform on the base metal and among the advantages of this technique is it able to

provide good durability and can be used on complex designs. Gold electroplate is also said to be less

expensive than that of gold-filled products. Finally if the electroplated layer is very thin and le

0.175 µm, the product is called gold wash.

Energy dispersive x-ray fluorescence (EDXRF) is a popular tool in the determination of

coating thickness and this had been used widely in many industries [3,4,5]. The analysis of metal

coating by using x-ray is an ideal application because x-rays achieve higher penetration depths than

comparable techniques. In this aspect, EDXRF have several advantages compared to the other

analytical techniques. EDXRF sy

coating thickness as w

hnique.

306

Experimental

carried out using the Baird Ex-310 instrument at MINT. Gold coating standards

roduced by Helmut-Fischer GMBH, Germany with thicknesses of 0.46, 0.90, 2.65 and 5.90 µm were

tive prolene plastic film. Each

standard was analyzed repeatedly for five times to ensure its accuracy. The Au thickness calibration

urve was constructed by measuring the intensity of Au under Lα peak with its respective thickness.

Similar experimental procedure was then applied during the measurement of gold-coated necklaces

and electrical connector. The Au coating thic e samples were then determined by using a

gression quantitative procedure.

Results And Discussion

In an EDXRF analysis, the transition of a higher energy level electron to its lower level will produce

cha e

analyze identification of the elements present through their energy

spectrum. Quantitative coating thickness measurement can be normally performed by two ways [1].

The first is called excitation and is the most common for single layer determination. When a sample is

exposed to an x-ray beam, the x-rays in the incident beam will interact with the coating material and

cause it to emit its own characteristic x-rays. In the absorption method, the interest is on the

cha e

absorbe e coating material and the amount of absorption is dependent on

the

. As

ther r was placed

front of the detector to reduce any error resulted from the dead time effect [7]. The EDXRF

pectrum shows characteristics energy peaks belonging to the L lines attributed by Au. The spectrum

also shows the presence of Fe substrate by the two smaller peaks (FeKα and FeKβ) located at left of

u peaks.

EDXRF analysis was

p

used for constructing the thickness calibration curve. The standards were analyzed by placing each of

these standards in a sample cup that is enclosed with an x-ray penetra

c

kness of thes

re

ract ristics x-ray that will be channeled to the detector [6]. The presence of a multi-channel

r card in the computer enables the

ract ristic x-rays produced by the substrate material. The x-rays emitted by the substrate are

d as they passed through th

type of coating and its thickness.

A typical EDXRF spectrum of a standard Au coating sample is as that shown in Figure 1

e was considerably high signal counts registered by using this x-ray energy, a Mo filte

in

s

A

307

Figure 1. EDXRF spectrum of Au coating standard

The energy spectral intensity data for standards and samples were processed by least-square

regression analysis with statistical evaluation carried out after repeating each analysis 5 times. In this

study the intensity of Au Lα was then correlated with the certified thickness of the different gold

standards using the excitation method (Figure 2).

Figure 2. Calibration graph for Au thickness coating

The excitation curve for very thin coating (<0.90 µm Au) is linear, that is, there is an

approximate straight-line relationship between x-ray intensity and thickness with a correlation value,

308

R2 of 0.998 (Figure 3). Beyond this an exponential relationship is establish for the intensity and

coating thickness. A quantitative analysis regression equation as that shown below was then applied

to measure the coating thickness [8];

Ci = Ao + AiIi (1)

where;

Ii is the radiation intensity of gold (kilocounts per second)

Ai is the slope

o is the intercept A

Ci is the coating thickness of gold

Gold coating thickness measurement on three different samples was then performed using the

these three samples.

above-developed quantitative procedure. These samples include 2 gold-coated necklaces that are

purchased from a night market and a direct selling company respectively. The other sample is a phone

connector produced from a factory in Sg. Petani, Kedah. The analytical procedure was done similar to

that performed on the standards with each sample analysed repeatedly for five times. Table 1 shows

he results obtained fromt

Table 1. Gold coating thickness analysis of different samples

Gold coating thickness (µm)

Analysis no. Gold necklace 1

(night market)

Gold necklace 2

(direct selling)

Phone connector

1 0.17136 3.3402 1.1876

2 0.17022 3.2153 1.3459

3 0.17135 3.2610 1.3911

4 0.16909 3.2384 1.2780

5 0.17135 3.4458 1.3911

Mean 0.1707 ± 0.0010 3.3001 ± 0.0940 1.3187 ± 0.0867

309

ysis for th f gold coating is v d by the EDXRF technique. This can be

d y the highly s and very tandard deviation ned for gold

n ple. The lo klace 1 sam chase from the nig arket has a

coating thickness of 0.1707 ± 0.0010 and this thickness is within the linear region of the calibration

g . From the mple can be classified as a

gold wash as the coating thickness is less than 0.175 µm [2]. A gold coating thickness of 3.3001 ±

in the analysis of another jewelry sample (gold necklace 2) purchased from a

irect selling company. The result sh tandard deviation value is bigger

and this relates to the bigger differences in the five analysis runs as compared to the previous sample.

e that there is a relationship between coating thickness

nd the time esti m, it is

estimated that time for its durabilit

value of 50 µinches [9]. The result also shows the developed procedure

highly accurate to measure gold coating thickness and is comparable with similar analysis

performed by the manufacturer.

The anal in layer o ery goo

emonstrated b consistent result small s obtai

ecklace 1 sam w price gold nec ple pur ht m

raph (Figure 2) classification of gold-coated articles, this sa

0.0940 µm was obtained

d ows that at this thickness the s

A major factor that may attribute for this is the thicker gold coating of this sample. This results to the

readings to fall at the exponential relationship between intensity and coating thickness as shown in

Figure 2.

Gold necklace 2 can also be classified as a gold electroplated article as the coating thickness

is way above the 0.175 µm limit for gold wash. And an interesting point to note about this jewelry

analysis result is that it can be co-related with the cost and durability of the sample. Gold necklace 2 is

much more expensive than that of gold necklace 1 and the former was purchased from a direct selling

company. It had been pointed in an earlier articl

a mated for its durability. For jewelry articles that has a thickness of 2.5 – 8.0 µ

y is 3 – 7 years while those having 0.5 – 2.5 µm has a lower

durability time of 1 – 3 years [2]. From the physical inspection of these two necklaces it show that the

colour for gold necklace 1 has deteriorated even though both are purchase at the same time.

Another sample that was analysed for its gold coating thickness is the phone connector. The

phone connector gives a mean result of 1.3187 ± 0.0867 µm (or 49.7150 µinches) that is almost

similar to the manufacturer’s

is

Conclusion

EDXRF proves to be a very valuable tool for the measurement of gold coating thickness. Besides

being non-destructive and fast, the analysis done on different samples show that the quantitative

technique developed is also highly accurate and comparable with similar analysis.

310

Acknowledgement

The authors wish to extend their gratitude to all parties that had supported the project in particular to

the MTEC staff and manager, BTI director and MINT management.

References

1. Veeco Instruments. (1996) U And XRF-500 Series XRF Coating

Thickness Measurement System, New York.

ser Manual XRF-400

2. An Overview Of Gold Filled Processes And Their Legal Classifications:

www.artisanplating.com

3. Nensel B. (2004) “Accuracy Of The Analysis Of Gold Alloy With EDXRF”, Proceedings

Denver X-rays Conference 2004.

4. Havrilla G.J., Miller T. and Doering E. (2003) “Characterization Of A Metal Alloy And Thin

Film Coating Using Elemental Imaging µXRF”, Proceedings Denver X-ray Conference 2003.

5. Kloos D. (2000) “EDXRF sing Proportional Counter Based

µXRF”, Proceedings 24th International Prcecious Metals conference, USA.

6. Bertin E.P. (1975) “Principle y Spectrometric Analysis”, 2nd Ed.,

n Bhd. (2001) Private Communication,.

Analysis Of Gold Carat Alloys U

s And Practices Of X-Ra

Plenum Press, New York.

7. Yokhin B. and Tisdale R.C. (1993) “High-Sensitivity Energy-Dispersive XRF Technology

Part 1: Overview Of XRF Technique” Am. Lab., 36G.

8. Baird. (1985) “Operation manual of EDXRF spectrometer”, Baird Corporation, Boston.

9. Tang Chee Guan, Huan Hsin Co. (M) Sd

311

APPLICATION OF SOLID-PHASE MICROEXTRACTION FOR THE DETERMINATION OF PESTICIDES IN VEGETABLE SAMPLES BY GAS CHROMATOGRAPHY WITH AN

ELECTRON CAPTURE DETECTOR

Chai Mee Kin1, Tan Guan Huat2 and Asha Kumari3

1Dept. of Science and Mathematics, College of Engineering, Universiti Tenaga Nasional, Km 7, Jalan Kajang-Puchong,

43009 Kajang, Selangor. [email protected] Fax:03-89263506

2,3Dept. of Chemistry, Faculty of Science,

Universiti Malaya, Lembah Pantai, 50603 Kuala Lumpur.

ABSTRACT. A solid-phase microextraction (SPME) method has been developed for the determination of 9 pesticides in 2

vegetables - cucumber and tomato - samples, based on direct immersion mode and subsequent desorption into the injection

port of a gas chromatograph with an electron capture detector (GC-ECD). The main factors affecting the SPME process such

as extraction time and temperature, desorption time and temperature, the effect of salt addition and fiber depth into the liner

were studied and optimized. The analytical procedure proposed consisted of a 30-minute ultrasonic extraction of the target

compounds from 1.0 g vegetable samples with 5 mL of distilled water. Then, the samples were filtered and topped up with

distilled water to 10 mL. The analytes in this aqueous extract were extracted for 15 minutes with a 100 µm thickness

polydimethylsiloxane SPME fiber. Relative standard deviations for triplicate analyses of samples were less than 10%. The

recoveries of the pesticides studied in cucumber and tomato ranged from 52% to 82% and the RSD were below 10%.

Therefore, the proposed method is applicable in the analysis of pesticides in vegetable matrices. SPME has been shown to be

a simple extraction technique, which has a number of advantages such as solvent free extraction, simplicity and

compatibility with the chromatographic analytical system.

Keywords: Solid-Ph

for pesticide analysis, most analytical instruments annot handle the sample matrices directly. In general, the analytical method involves processes such

as sampling, sample preparation, separation, detection and data analysis and more than 80% of the analysis time is spent of sampling and sample preparation steps that include homogenization of samples, extraction of the analytes with an organic solvent, and clean up of the final organic extract. Therefore, it is not an exaggeration to say that the choice of an appropriate sample preparation method greatly influences the reliable and accurate analysis of food. In contrast to conventional techniques, Solid Phase MicroExtraction (SPME) is a solvent-free extraction that minimizes sample preparation allowing the extraction and concentration steps to be focused into a single step. This technique, whose initial concepts were developed by Pawliszyn and co-workers in 1990 [1], is based on absorption of analytes onto a polymeric-coated fused-silica fiber,

ase Microextraction, GC-ECD, pesticides, vegetables

INTRODUCTION

One of the major fields in analytical chemistry is the development of faster and easier methodologies for characterization and quantification of trace compounds in complex matrices. A special attention is given to substances that can compromise food safety, such as pesticide. Pesticides are widely used for agricultural and non-agricultural purpose throughout the world. Although various methods, using highly efficient instruments such as gas chromatography (GC), high performance liquid chromatography (HPLC), Liquid chromatography (LC) and their combination

ith mass spectrometry (MS), have been developedwc

312

usually housed in a modified syringe. The total analytes retained in the fibers are thermally desorbed in the injector port and deposited at the head of the GC column. Due to its advantages over classic extraction methods, SPME has received increasing attention since its commercial introduction in the nearly 1990s [2]. SPME has been applied to the determination of several organic compounds especially in gas and liquid samples, but also in a few solid samples, in combination with both GC and HPLC determination. Two modes of application of SPME have been extensively reported [1]: Direct Immersion (DI-SPME) and Headspace (HS-SPME) extraction. In DI-SPME, the fiber is directly immersed in the liquid sample or in the sample suspension and the analytes are transported from the sample matrix to the fiber coating. In headspace extraction mode, the analytes are extracted in a three-phase system: sample (liquid or solid), headspace, and fiber coating. SPME has been successfully applied to the determination of pesticide residue analysis in water, soil, food and biological samples as reported in recent reviews published by Beltran et al. [3] and Kataoka et al. [1]. Water samples are by far the most widely analyzed by this technique [4-6].

The number of ill limited; the eadspace mode is the most attractive approach in this field [7-12]. Analysis of other samples such as

esticide determination in food samples by SPME derives from e complexity of these matrices, which makes an extraction of the sample prior to determination by

irect immersion SPME necessary in most of cases. This problem can be overcome if headspace PME is applied, as described in several papers dealing with pesticide residue determination in fruits

ber of papers related to determination of volatile compounds in food

uantification; in most cases it is necessary to use calibration curves prepared using blank matrix, and internal standards [20].

applications of SPME to complex matrices such as biological fluids is st

hsoil [13-16] or food commodities [1, 17-18] is generally based on a solvent extraction of the analytes before application of SPME. The low number of references about pthdS[19-21] or in a large numommodities [22-25]. c

Determination of non-volatile pesticides has received increasing attention in the recent years in order to solve some of the problems related with the application of DI-SPME in complex matrices. Several papers deal with direct immersion of the SPME fiber into a slurry of fruit with water [19,26]. Complex matrix problems can be solved by prior extraction of pesticide and the subsequent application of DI-SPME over the separated aqueous extract. Once the aqueous extract is obtained, the presence of interfering substances can reduce the efficiency of SPME. This problem can be overcome by simply diluting the extract in order to simplify the matrix complexity [27-28]. Still another problem, closely related with pesticide residue determination in fruits by SPME, is the difficulty of qstandard addition calibration, The aim of this work is to investigate the feasibility of developing a single-step clean up enrichment procedure for pesticides extracted from vegetables based on SPME prior to gas chromatography with electron capture detection (GC-ECD). Nine pesticides: Carbaryl, Diazinon, Chlorothalonil, Malathion, Chlorpyrifos, Quinalphos, Profenofos, Alpha-Endosulfan, Beta-Endosulfan were selected as the model compounds because residues of these compounds are very often detected in vegetable samples. Table 1 showed the properties of nine selected pesticides. In this study, SPME-GC-ECD conditions have been optimized for the target compounds. The developed procedure was then successfully applied to the analysis of vegetable samples such as cucumber and tomato.

313

Table 1: Name, Molecular Form hemical Class of the selected Pesticides.

ula, Molecular Weight, C

Name Molecular Formula Molecular Weight Chemical Class Carbaryl C12H11NO2 201.22 Carbamate Diazinon C12H21N2O3PS 304.35 OP Chlorothalonil C8Cl4N2 265.92 OC Malathion C10H19O6PS2 330.36 OP Chlorpyrifos C9H11Cl3NO3PS 350.62 OP Quinalphos C H O N PS 298.18 OP 12 15 3 2

Profenofos C11H15BrClO3PS 373.60 OP α-Endosulfan C9H6Cl6O3S 406.96 OC β-Endosulfan C9H6Cl6O3S 406.96 OC

EXPERIMENTAL

Chemicals and Reagents All solvents used were HPLC grade. Methanol was purchased from Fischer Scientific, Loughborough, U.K. Deionized water and methanol were filtered through a 0.45 µm membrane filter purchased from Millipore. The use of high purity reagents and solvents help to minimize interference problems,

esticide standards (carbaryl, diazinon, chlorothalonil, malathion, chlorpyrifos, quinalphos, rofenofos, α-endosulfan, β-endosulfan) were > 95% pure and purchased from AccuStandard Inc.

New Haven CT, USA. Stock solutions of each pesticide at different concentration level, 50-2000 g/kg were prepared in methanol and stored at 4 oC. Preparation of different concentration level of

stock solution is due to their sensitivity to the ECD detector. Working standard solutions of pesticides

results from d veryday. 1-chloro-4-fluorobenzene (2mg/kg) was used as internal standard to compensate for sample

and was added to the vial r to GC

Gas Ch graphy – Capture Detector (GC-ECD) A Shimadzu GC 17A version 2.21 gas ch c pture detector was used. A SGE BPX5, 30m x 0.32 mm id capillary column with a 0.25 µm film ed in c mp gram: initial te ure 120 oC, th C/min r temperature at 250 oC, held f The total run s 23.07 min. The injector t at 240 the detecto 00 ogen gas (9 ) was u ier gas as flow at c linear velocity and the pressure at 94 kPa and

eters affecting the SPME of the vestigated from aqueous solution (i.e. extraction time and temperature, desorption time

and temperature, the effect of salt addition, stirring speed of the solution and fiber depth into the

pp

m

mixture were prepared by volume dilution in distilled water. In order to avoid the influence on the the possible degradation of pesticides, the working solution was freshly prepare

e prio analysis.

romato Electron

romatograph with an ele tron ca ECDwas us

oombination with the following oven te erature pro mperat en 7 amp to final or 4.5 min. time waemperature was oC and r temperature was at 3 oC. Nitr 9.999%sed as the carre split mode ratio of 1:36.

with a g 24.4 cm/seth

SPME Procedure The SPME fiber holder for manual extraction and the fibers of polydimethylsiloxane (PDMS, 100 µm film thickness) were purchased from Supelco (Bellefonte, PA, USA). SPME fibers were conditioned by heating at 250 oC for 0.5 hour in the gas chromatography (GC) injection port according to the manufacturer recommendations in order to remove contaminants and to stabilize the polymeric phase.

reliminary experiments were carried out to optimize the main paramPpesticides in

314

liner). In these studies, distilled water samples spiked with the appropriate amount of the standard solution was used. After optimization, a typical experiment consisted of the direct immersion of the conditioned fiber into the spiked water sample, 10mL in a 15 ml clear glass vial and capped with a PTFE-faced silicone septum (Supelco). The SPME holder needle was inserted though the septum and the fiber was directly immersed in the sample solution for 15 minutes under magnetic stirring at room temperature (25 oC) in order to improve mass transfer from the aqueous sample into the fiber coating. After extraction, the fiber was withdrawn into the holder needle, removed from the vial and immediately introduced into the GC injector port for 7 min at 240 oC for thermal desorption in a split mode injector. Calibration curves were constructed by SPME of the target compounds from aqueous samples spiked at 7 concentration levels and the constant volume of internal standard under above experimental condition. Three extractions were made for each concentration level of mixture solution. The calibration graph was plotted by the ratio of the peak area of the analyte against the peak area of the internal standard from the spiked samples versus the concentration of the analyte. These calibration

nes were used for quantification in subsequent experiments.

RESULTS AND DISCUSSION

Method Optimization Preliminary experiments were performed by direct injection of pesticides for GC-ECD conditions optimization; the temperature program developed was capable of a good separation of the investigated analytes. In order to developed the SPME described method for pesticides selected extraction in vegetables, several parameters such as extraction time and temperature, desorption time and temperature, the effect of salt addition, stirring speed of the solution and fiber depth into the liner were studied. On the basis of the results previously published for the target compounds, a 100 µm PDMS fiber was chosen as this material has been reported to have satisfactory extraction efficiency for a variety of compounds, including pesticides selected in this study. The 100 µm PDMS fiber (a non-polar phase) is recommended in the literature because it is a rugged liquid coating able to withstand high injector temperature up to 300 oC. Fibers coated with thicker films required a longer time to achieve extraction equilibrium, but might provide higher sensitivity due to the greater mass of the analytes that can be extracted.

Effects of

bat re. he temperature effect was evaluated by varying the temperature from 25 to 70 C. An increase in

li

Vegetable Samples In order to evaluate the pesticide recoveries, 2 types of vegetables, cucumber and tomato were obtained from pesticide free farms under study. 1.0 g of vegetable samples was finely chopped and placed in a 15ml clear glass vial and capped with a PTFE-faced silicone septum. 5 mL of distilled water was added and spiked with three concentration levels of stock solution. The mixture was shaken for 30 minutes in an ultrasonic bath. Then, the samples were filtered, added with internal standard and topped up with distilled water to 10 mL. Pesticides were then extracted by direct dipping of the PDMS fiber in the solution. Recoveries of pesticides were determined by comparison of the ratio of the peak area of the analyte against the peak area of the internal standard from the spiked samples with that of the standard calibration solutions.

Extraction Temperature and Time

In order to study the effect of temperature on the extraction process, vials were immersed in a water h heated by the magnetic stirring unit. A thermometer was used to monitor the water temperatu

oT

315

extraction temperature causes a extraction rate and a si rease in the distribution constant between the analytes iber [27 s of t cide c was performed at room temperature for the subsequent experiments. T e profile f selected fiber btained by plo e detector response (peak area) versus the extraction or each pestici o obtain the partition equilibrium curve (figure 1). Blank aqueous 0.1 mL sta olution were zed at e onditions d in the SPME edure. Sorpti ofiles indicated that a s e higher tha inutes is nec to reach the equilibrium. According to the l 9-31], the n time can be ened by work on-equilibriub unt of ana sorbed from th ple onto the proportional initial concentration in the sampl , if the agitation and the sampling re held consta ongst samples. Thus, considering a compromise betw n the extraction time and the chromatographic

raction time of 15 minutes was selected for further experiments. This time still ducible extraction response for all pesticides while minimizing analysis time.

n increase in the multaneous decand the f ]. The analysi he 9 pesti

ompounds

he sorption tim or the was o tting th time f de in order t samples (10mL) spiked at ndard s analy

xperimental c escribed proc on time prampling tim n 30 m essary iterature [1,12,2

o sorptio short ing in n m condition

ecause the am lyte ade matrix

e sam fiber is time a

to thents am

eeanalysis time, an extallowed a good, repro

5

10

15

20

25

30

35

40

45

Peak

Are

a (x

100

000)

Carbaryl

Diazinon

Chlorothalonil

Malathion

Chlorpyrifos

Quinalphos

Alpha-Endo

Profenofos

05 8 10 12 15 20 25 30

Extraction Time (min)

Beta-Endo

Figure 1: Peak area versus extraction time for 9 investigated pesticide

ption Temperature and Time

he temperature of GC injector and desorption time were tested in order to guarantee the complete

nd 2 according to the recommended temperature range indicated by the

analy y re com o

mperature me and can result in the bleeding of the polymer, causing blem

Effects of Desor

Tdesorption of pesticides to avoid carryover. For the PDMS fiber, temperatures ranging between 200

80 oC were tested (selectedamanufacturer). High desorption temperature can enhance the process but they can also degrade

tes. Desorption at 200 and 230 oC was not capable of desorbing completely the analytes; thewe pletely removed from the coating at 240 – 280 C and not much significant differences were observed within this range of temperature. Hence a temperature of 240 oC was selected since high

s can shorten the coating lifetitepro s in the separation and quantification [29].

316

0

2

4

6

8Pe

ak A

rea

(x 1

0000

0) 10

12

0 2 4 6 8 10 12

Desorption Time (min)

Carbaryl

Diazinon

Chlorothalonil

Malathion

Chlorpyrifos

Quinalphos

Alpha-Endo

Profenofos

Beta-Endo

Figure 2: Peak area versus desorption time for 9 investigated pesticide.

ption profiles of the pesticides were obtained by plotting the detection respoDesor nse versus different esorption times, 1 – 10 minutes. Desorption profiles showed that a 6 minute-period was sufficient to

desorb pesticides in the GC injector port (Figure 2); therefore a 7 minute-period was chosen to uarantee a reproducible desorption.

add

soluble fiber can be increased if the solubility of the analytes in water is decreased by adding sodium

eterm ium chloride. Result

be t rthin la salt around the fiber, which decreases the extraction efficiency [29].

nd h showed the responses increased if the

thequilibrium time progressively decreases with increasing agitation rate, faster agitation tends to be

measuf ext .

Effec

reaolumn entrance and the center of the hot injector zone.

d

g

Effects of Salt Addition

The ition of salts into the samples can modify the extraction efficiency, because the partition coefficients are partially determined by matrix-analyte-fiber interactions [29]. Pesticides that are more

e in water have a lower affinity for the fiber coating. The amount of these analytes extracted by thchloride to alter the ionic strength [27]. The effect of increasing the ionic strength of the sample was

ined with samples containing no salt, 5, 10, 15, 20 and 25% (w/v) of soddshowed that the amount of compounds extracted decreased when the salt concentration increased. The

s esults were obtained when no salt was added; this could possibly be due to the formation of a yer of

Effects of Stirring Speed The use of a magnetic stirrer allows the control of the stirring speed as well as the mode of stirring,

ence a cyclic change in stirring direction. The resultsastirring speed is increased which agrees with the fact that SPME is a technique based on equilibrium and at good diffusion through the phases is essential to reach equilibrium faster. Although the

uncontrollable and the rotational speed might cause a change in the equilibrium time and poor rement precision. A constant gentle stirring speed was selected in this study to increase the rate ractiono

ts of Fiber Depth into the Liner

The effect of the fiber depth into the liner was also checked, and the results showed that peak areas inc sed when the depth of the fiber into the injector glass-liner was higher, which is closer to the c

317

Method performance After optimization of all the variables considered, the recommended procedure was established as

llows: extraction of 10 mL of water sample containing no salt under magnetic stirring for 15 min at te

min. ater sa ed conditions for the SPME procedure, quality parameters of the

calcul

eranalyt that of the peak area of internal standard versus the analyte concentration

generate the calibration curves, a statistical regression model was applied to obtain the corresponding values for slope and intercept for each compound. The SPME procedure showed a linear behavior in the ranges tested with r2 values > 0.9900. Linear ranges and determination coefficients (r2) obtained for each pesticide are given in Table 2. The loss of linearity observed at higher concentrations can be justified due to overloading of the SPME fiber capacity. The detection limit (LOD) was calculated by comparing the signal-to-noise ratio (S/N) of the lowest detectable concentration to a S/N=3. A S/N of 10 was applied for the calculation of the quantification limit (LOQ). The results obtained are shown in Table 2. Table 2: Coefficients (r2), linear range, limits of detection (LOD) and limits of quantification(LOQ) of

the investigated pesticides using the optimized SPME extraction method. Name R2 Linear Range (mg/kg) LOD (mg/kg) LOQ (mg/kg)

foroom mperature using a PDMS, 100 µm fiber coating and subsequent desorption at 240 oC over 7

The optimum procedure developed was applied to the extraction of nine pesticides in spiked mples. With the selectw

SPME-GC-ECD method such as linearity, limits of detection and quantitation, and recovery were ated.

The linearity of the method was tested using a series of aqueous solution (distilled water) in the diff ence concentration range (7 levels, three replicates for each level). After plotting the ratio of

e peak area relative to to

Carbaryl 0.9976 0.2 – 200 0.01 0.05 Diazinon 0.9968 0.05 – 50 0.005 0.02 Chlorothalonil 0.9988 0.02 – 20 0.001 0.005 Malathion 0.9965 0.05 – 50 0.005 0.02 Chlorpyrifos 0.9986 0.005 – 5 0.0005 0.001 Quinalphos 0.9985 0.05 – 50 0.005 0.02 Profenofos 0.9941 0.01 – 10 0.001 0.005 α-Endosulfan 0.9952 0.005 – 5 0.0005 0.001 β-Endosulfan 0.9972 0.005 – 5 0.0005 0.001

Vegetable Samples The developed method has been applied to the vegetable samples, cucumber and tomato, treated as described in the Experimental section. From Figure 3, it is clear to show that all the target analytes were detectable in the sample and appeared completely separated from interfering peaks. The extraction efficiencies were calculated by comparing the chromatogram (Figures 3) obtained from the extracts of the spiked samples by SPME with those obtained by direct GC injection of non-extracted (Figure 4). It is shown that SPME is effective in the extraction of all the pesticides investigated without absorbing any other unwanted compounds from the samples.

318

Intensity

Figure 3 : Chromatogram on recovery of spiked cucumber and extracted by SPME.

to study the accuracy. These tests were based on the addition unts of standard solution of pesticides to the vegetable samples. The study was carried

Recovery tests were performed in order of known amoout in triplicate at three concentration levels. The peak areas obtained when these samples were analyzed by the same procedure were compared with the standard calibration curves. Mean recoveries and RSD obtained in the analysis of fortified cucumber and tomato samples are listed in Table 3. For fortified cucumber samples, the recoveries were between 53 – 75 % and for the tomato, the recoveries were between 53 – 82 % with is quite similar to that of the fortified cucumber. The precision determined using the same conditions was good, with the vast majority yielding relative standard deviations (RSDs) below 10 %.

Figure 4: Chromatogram on recovery of spiked cucumber and direct injection

able 3: Average recoveries and relative standard deviations (RSDs) from three representative commodities fortified vegetable samples using the optimized SPME extraction method.

5 20 15 10 min

6.105 19.690

200000

300000

4000

16.667

16.888

18.543

20.026

00 22.231 19.698 Internal standard : 5.477 min (2 mg/kg) Carbaryl : 10.136 min (40 mg/kg)

.794 min (10 mg/kg)

T

Intensity

0

0

10000

20000

30000 5.484

11.386

16.669

16.884

18.551

22.226

20.021

5 0

0

20 15 10 min

5.477 10.136 6.100

100000

13.794 in (2 mg/kg)

Diazinon : 13Chlorothalonil : 14.835 min (4 mg/kg) Malathion : 16.667 min (10 mg/kg) Chlorpyrifos : 16.888 min (1 mg/kg) QuinaAlpha Endosulfan: 19.69Profenofos : 20.026 mBeta Endosulfan : 22.231 min (1 mg/kg)

lphos : 18.543 min (10 mg/kg) 8 min (1 mg/kg)

14.835 15.415

319

Name Cucumber (n=3) Tomato (n=3) Recovery (%) RSD (%) Recovery (%) RSD (%) Carbaryl 74.10 82.17 1.26 8.22 Diazinon 53.96 1.43 54.13 1.57 Chlorothalonil 58.26 1.27 56.44 1.00 Malathion 75.03 2.11 71.79 0.47 Chlorpyrifos 55.36 8.93 56.90 9.30 Quinalphos 54.76 2.53 52.57 0.99 Profenofos 56.47 3.94 58.41 5.99 α-Endosulfan 60.09 6.05 53.08 3.83 β-Endosulfan 65.27 4.39 58.40 6.92

ONCLC

USION

fast, simple, solvent free screening method based extraction of a 1.0 g

CKNOWLEDGEMENT

. Betran J, Lopez F.J, Hernandez F (2000), “Solid-phase microextraction in pesticide residue analysis.”, J. of Chromatography A, 885, 389-404.

. Tomkins BA, Barnard AR (2002), “Determination of organochlorine pesticides in ground water using solid-phase microextraction followed by dual-column gas chromatography with electron-capture detection.” J. of Chromatography A, 964, 21-33.

7. Hernandez F, Pitarch E, Beltran J, Lopez FJ (2000), “Headspace solid-phase microextraction in combination with

gas chromatography and tandem mass spectrometry for the determination of organochlorine and organophosphorus pesticides in whole human blood.”, J.of Chromatography B, 769, 65-77.

A on a 30 min ultrasonic vegetable samples with distilled water and subsequent SPME of the analytes from the aqueous solution and detected by gas chromatography with an electron capture detector has been developed for the determination of nine pesticides. The main experimental parameters affecting the SPME step were optimized. This method offers very low detection limits for all nine pesticides. The recoveries of the pesticides studied in cucumber and tomato ranged from 53% to 82% and the RSD were below 10%. Therefore, the proposed method is applicable in the analysis of pesticides in vegetable matrices. SPME has been shown to be a simple extraction technique, which has a number of advantages such as solvent free extraction, simplicity and compatibility with the chromatographic analytical system. A The authors acknowledge the financial support provided by the Universiti Tenaga Nasional and Ministry of Education to pursue the research work. The authors would like to thank Universiti of Malaya for providing the opportunity and facilities to undertake the research. REFERENCE

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Chromatography A, 880, 35-62. 2. Beltran J, Peruga A, Pitarch E, Lopez, FJ and Hernandex F (2003), “ Application of solid-phase microextraction

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z JL ( of oxnd g phy-m Chro

14. Zambonin CG, Palmi

i G, boni MK (2001), “Fast determination of ph1Chromatography A, 911, 135-141.

16. Bouaid A, Ramos L, Gonzalez MJ, Fernandez P, Camara C (2001), “Solid-phase microextraction method for the

determination of atrazine and four organophosphorus pesticides in soil samples by gas chromatography.” J. of Chromatography A, 939, 13-21.

17. Eisert R, Jackson S, Krotzky A (2001), “Application of on-site solid-phase microextraction in aquatic dissipation

studies of profoxydim in rice.” J. of Chromatography A, 909, 29-36. 18. Fidalgo N, Centineo G, Blanco E (2003), “Solid-phase microcextraction as a clean-up and preconcentration

procedure for organochlorine pesticides determination in fish tissue by gas chromatography with electron capture detection.” J. of Chromatography A, 1017, 35-44.

19. Simplicio AL, Boas LV (1999), “ Validation

is TA (2002), “Headspace solid-phase microextract20.

3365. 1. Matich AJ, Rowan DD, Banks NH (1996), “2

apple volatiles.” Anal. Chem. 68, 4114-4118. 22. Holt Ru (2001), “Mechanisms Effecting analysis of volatile flavour components by solid-phase microextraction

and gas chromatography.” J. of Chromatography A, 937, 107-114. 23. Mestres M, Busto O, Guasch J (1998), “Headspace solid-phase microextraction analysis of volative sulphides and

disulphides in wine aroma.” J. of Chromatography A, 808, 211-218. 24. Song J, Gardner BD, Holland JF, Beaudry RM (1997), “Rapid analysis of volatile flavour compounds in apple

fruit using SPME and GC/Time-of-Flight Mass Spectrometry.” J. of Agricultural and Food Chemistry, 45, 1801-1807.

25. Song J, Fan L, Beaudry RM (1998), “Application of solid-phase microextraction and Gas Chromatography/Time-

of

321

28. Sen NP, Seaman SW, Page BD (1997), “Rapid semi-quantitative estimation of N-nitrosodibutylamine and N-

nitrosodibenzylamine in smoked hams by solid-phase microextraction followed by gas chromatography thermal energy analysis.” J. of Chromatography A, 788, 131-140.

29. Otero RR, Ruiz CY, Grande BC, Gandara JS (2002), “Solid-phase microextraction-gas chromatographic-mass

spectrometric method for the determChromatography A, 942, 41-52.

ination of the fungicides cyprodinil and fludioxonil in white wines.” J. of

0. Zambonin CG, Cilenti A, Palmisano F (2002), “ Solid-phase microextraction and gas chromatography-mass spectrometry for the rapid screening of triazole residues in wine and strawberries.” J. of Chromatography A, 967, 255-260.

31. Michelle LR, Jennifer SB (2001), “ Analysis of fine ant pesticides in water by solid-phase microextraction and gas

chromatography/mass spectrometry of high-performance liquid chromatography/mass spectrometry.” Analytical Chimica Acta, 436, 11-20.

3

322

APPLICATION OF SOLID PHASE MICROEXTRACTION (SPME) IN PROFILING

HYDROCARBONS IN OIL SPILL CASES

Zuraidah Abdullah Munir*, Nor’ashikin Saim, Nurul Huda Mamat Ghani

Department of Chemistry, Faculty of Applied Sciences, Universiti Teknologi MARA 40450 UiTM Shah Alam, Selangor, Malaysia.

e-mail: [email protected] Abstract. In environmental forensic, it is extremely important to have a fast and reliable method in identifying sources of spilled oil and petroleum products. In this study, solid phase microextraction (SPME) method coupled to gas chromatography-mass spectrometry was developed for the analysis of hydrocarbons in diesel and petroleum contaminated soil samples. Optimization of SPME parameters such as extraction time, extraction temperature and desorption time, was performed using 100-µm polydimethylsiloxane (PDMS) fiber. These parameters were studied at three levels by means of a central composite experimental design and the optimum experimental conditions were determined using response surface method. The developed SPME method was applied to determine the profiles of hydrocarbons in several oil contaminated soil sample. The SPME method was also used to study the effects of weathering on the profiles of hydrocarbons in unleaded gasoline, diesel and kerosene contaminated soil samples. After several days, significant losses of the lighter hydrocarbons were observed compared to the heavier ones. From these data, SPME method can be used to differentiate possible candidate sources in oil spill cases. Keywords: Profile of hydrocarbon, solid phase microextraction (SPME), oil spill Introduction Gasoline, diesel and kerosene are all created from crude oil by a variety of refining and distillation processes. Each product is produced by the combination of multiple individual hydrocarbon compounds all of which have slightly different vaporization and boiling temperatures. Gasoline is the combination of many lower boiling range compounds while the middle boiling range compounds are used in differing proportions to create kerosene and diesel. The profile of hydrocarbons in oil may hence be used to characterize the oil. This enables the identification of the candidate source of oil spill cases. In forensic chemistry, ability to identify the sources of an oil spill is very important and hydrocarbon fingerprinting method is now realized as one of the fastest and reliable method for identifying the origin of oil spill cases. In th ith mass spectrometry

ils. The simplicity of operation, sensitivity, selectivi y, and the solvent-free nature of the

sis to separate and evaluate the effects of the various ctors involved. The optimized SPME method was used to analyze the effect of weathering on three pes of oils: unleaded gasoline, diesel and kerosene.

is study, a solid phase microextraction (SPME) method coupled to gas chromatography w detector (GC-MSD) was or analyzing the profile of several types of developed f

ty, portabilitoSPME method makes it a powerful tool for sample introduction method for gas chromatographic analyses of organic chemicals [1]. It is based on the enrichment of analytes on a polymer or adsorbent-coated fused-silica fiber either directly to the sample or its headspace. The extraction efficiency of SPME technique is dependent on several experimental parameters such as the extraction time, extraction temperature and desorption time [2,3]. These operating parameters were optimized using an experimental design approach that consisted of three stages; identifying the factors which may affect the result of an experiment, designing the experiment so that the effects of uncontrolled

ctors are minimized, and using statistical analyfafaty

323

EXPERIMENTAL

Preparation of spiked sample Three types of oil (unleaded gasoline, diesel and kerosene) were used in this study. About 1 L of each type of oil was poured into three separate plots of soil. After 2 weeks, the contaminated soil for each plot was mixed thoroughly, sieved and stored in an amber bottle at -4 ˚C until analysed. For the weathering study, three plots of soil measuring 2’ x 1.5’ each were chosen for three types of oil (unleaded gasoline, diesel and kerosene). Each plot was divided into 20 small sections. About 1 L of oil sample was poured into each dedicated plot. For each analysis, 100 g of two small sections of soil were thoroughly mixed and a 5 g sample was placed in a headspace vial (5 mL volume) and capped for SPME analysis. Soil was analysed 1 day, 2 days, 1 week, 2 weeks and 1 month after oil spillage.

Solid phase microextraction (SPME) A 100-µm polydimethylsiloxane (PDMS) fiber (Supelco, Bellafonte, Pennsylvania, USA) was conditioned in a hot GC injection port at 250 °C for 30-60 min prior to sample extraction. In the optimization study, the SPME needle was inserted through the septum of the vial and the fiber was released and exposed to the headspace of the sample at a specified temperature (maintained using a water bath) for a specified extraction time. The fiber was then withdrawn, SPME needle was removed from the headspace and immediately injected into the gas chromatography (GC) with a desorption time of 35 sec. For the weathering study, the sample was extracted at 90 °C for 45 min. The compounds were then transferred into the GC with desorption time of 35 sec.

Experimental design

tatistical software package Design-Expert 6.0.6, an expert system for the design and analysis of

f SPME for the extraction of hydrocarbons in soil using three experimental variables (extraction

on temperature and extraction time. The response ariables selected were the GC area count for several common compounds of unleaded gasoline,

diesel and kerosene. The response vari the gas chromatograph area count for idecane, hexadecane, and octadecane. The design matrix of the central composite design is shown in

lumn used was a HP-5MS fused silica capillary column, 30.0 m x 250 µm I.D d 0.25 µm capillary thickness. Injections were made in the splitless mode. The temperature

rogrammed was set at an initial 60 °C for 2 min, followed by an increase by 10 °C min-1 to 200 °C d held for 15 min. Both the injector temperature and the detector temperature are set at 250 °C.

Sexperiments was purchased from Stat-Ease Inc., Minneapolis. Preliminary work on the optimization otemperature, extraction time and desorption time) showed that the desorption time was not significant within the range 20 to 50 seconds and from the response surface analysis, optimum extraction was achieved at desorption time of 35 sec. Optimization using central composite design was then focused on two experimental variables, namely extractiv

ables selected weretrTable 1. The order of these experiments was randomized to remove any systematic error.

GC-MS analysis GC-MS were performed on Agilent Technologies 6890 Network GC System with Agilent Technologies 5973 inert Mass Selective Detector. The flow rates of gases were set to manufacturer’s specifications. The coanpan

324

Table 1: Central composite design of the optimization experiment

Run Order Extraction Time (min) Extraction Temperature (ºC)

1 50.0 60.0 2 80.0 60.0 3 50.0 90.0 4 80.0 90.0 5 65.0 75.0 6 65.0 75.0 7 43.8 75.0 8 86.2 75.0 9 65.0 53.8

10 65.0 96.2 11 65.0 46.0 12 65.0 40.0

Results And Discussion

Optimization of SPME conditions

The results from the central composite design were fitted to a quadratic model. Analysis of variance (ANOVA) was performed on the design in order to determine which variables (A:extraction time and B:extraction temperature), if any, had a significant effect on the recovery of each compound. From the statistical analysis of the experimental design, it was found that extraction temperature was the important factor influencing the amount of hexadecane and octadecane extracted from soil. The influence of temperature on the extracted amount of hexadecane and octadecane was further studied using spiked sample with SPME extraction time of 45 min and desorption time of 35 sec. It was found that in both cases, the amount extracted increases as the extraction temperature increases, but at temperature more than 90 °C the amount of hexadecane and octadecane extracted decreases. Based on he n mperature 90 °C and desorption time 35 sec.

Profile ample

mplex mixture of hydrocarbons compounds predominantly in the range of C3 – C12. It the lig

undecane, dodecane, tridecane and in.

romatics hydrocarbons. Major compounds in kerosene are dodecane, tridecane, tetradecane and entadecane. The hydrocarbons of kerosene were eluted in the range of 7.00 min to 13.50 min [Figure (b)].

tte

se analyses, the optimum operating conditions for SPME were: extraction time 45 min, extractio

of hydrocarbons in spiked s

The optimized SPME method was applied in the extraction of unleaded gasoline, diesel and kerosene from spiked soil samples. Gasoline is a cois ht distillate product of petroleum containing more lower molecular weight hydrocarbons but higher fraction of both light hydrocarbons and aromatics. It contains about 41% alkanes with

tetradecane as major compounds. In the profile of hydrocarbons in gasoline [Figure 1(a)], the hydrocarbons were eluted in the range between 5.50 min to 12.00 m Kerosene is a light end middle distillate of petroleum. It is composed of hydrocarbons mostly in the range of C9 – C16. It contains 50.5% aliphatic hydrocarbons and 30.9% naphthenes, the rest being ap1

325

Diesel is a higher boiling point fraction composed of essentially C to C aliphatic hydrocarbons. It has a iesel contains 55 n chemical composition to kerosene with the exception of additives. As shown in Figure 1, the hydrocarbon profile of diesel [Figure 1(b)] is quite similar to that of kerosene [Figure 1(c)], with additional compounds eluted up to 18.00 min.

Effects of weathering on oil hydrocarbon fingerprinting

weathering process, in particular for the light petroleum products. The locomponents tend to volatilize more rapidly than the components of higher hydrocarbon profile of the spiked soil was obtained using SPME method uconditions. Figure 2 shows the profile of unleaded gasoline in soil after weathering. It was found that after 1 week, the more volatile compounds, dodec

10 25 wide range of polyaromatic hydrocarbons such as naphthalenes and phenanthrenes. D

% paraffins, 24% aromatics, 12% naphthenes, and 5% olefins. It is similar i

(a) (b)

3

2

4

5 1

2

3

4

6

8

7

Kerosene

4

1

3

2

5

6

7

(c)

5

When oil or petroleum products are accidentally released to the environment, thsubjected to a wide variety of weathering process that can affect their chemical pshort term after a spill (hours to days), evaporation is the single most impo

326

Diesel

9

Figure 1. GC-MS total ion chromatogram of (a) unleaded gasoline (b) diesel and (c) kerosene recovered from spiked soil sample. Identification of compounds: 1: undecane 2: dodecane 3: tridecane 4: tetradecane 5: pentadecane 6: hexadecane 7: heptadecane 8: octadecane 9: nonadecane

1

Unleaded gasoline

wer boiling points boiling points. The sing the optimized differing levels of ane and tetradecane

ey are immediately roperties [4]. In the rtant and dominant

327

r reduced by 97%.

line in soil sampled (a) 2 days, (b) 1 week and (c) 2 weeks after spillage.

igure 3 shows the profile of diesel in soil after differing levels of weathering. These chromatograms ed a decreased in peak intensity due to volatilization. It was found that after 1 week, the

ile compound (dodecane) was evaporated by 80% while tetradecane, pentadecane, exadec

were reduced by 46% and 45% respectively while naphthalene 1, 6, 7-trimethyl was reduced by less than 1%. After 2 weeks, dodecane and tetradecane were reduced by 98% while naphthalene 1, 6, 7-trimethyl was reduced by 96% and after one month the more volatile compounds (dodecane and tetradecane) were undetected while the amount of naphthalene 1, 6, 7-trimethyl was furthe

(a)

(b)

Figure 2. Hydrocarbon fingerprint of unleaded gaso

(c)

Fclearly show

ost volatmh ane and heptadecane were reduced by 69%, 34%, 26% and 21% respectively. However, after one month the more volatile compounds (dodecane, tetradecane and pentadecane) had disappeared while the amount of hexadecane and heptadecane had reduced to 98%. The least volatile component in diesel (octadecane) was reduced by 89%.

(a)

(b)

Figure 3. Hydrocarbon fingerprint of diesel in soil sampled (a) 2 days, (b) 1 week and (c) 2 weeks after spillage.

(c)

Figure 4 shows the profile of kerosene in soil after differing levels of weathering. After 2 weeks,

s in kerosene had almost disappeared. Tetradecane and pentadecane had ile heptadecane had 86% evaporated. After 1 month these compounds were

ue, which enables the simultaneous extraction and pre-concentration steps, has been th

most of the compounddisappeared by 96% whalmost insignificant in the soil sample analysed.

CONCLUSIONS The use of SPME-GC-MSD provides a reliable method for hydrocarbon fingerprinting of oil from soil. SPME techniq

e method of choice for the analysis of these compounds in soil because it is fast, solvent-less extraction method, inexpensive and can handle the matrix sample directly. Therefore, it reduces analysis time (allowing processing a higher number of samples) and avoids loss of analytes. Study of weathered oils of spiked soil samples using SPME was able to show the change in the profiles of their chemical properties.

328

329

Figure 4. Hydrocarbon fingerprint of kerosene in soil sampled (a) 2 days, (b) 1 week and (c) 2 weeks after spillage.

The authors would like to acknowledge financial support from IRDC, Universiti Teknologi MARA r fund ng this project (IRDC Project number: 600-IRDC/ST 5/3/789).

eferences

. Hook, G.L., Kimm, G.L., Hall, T., and Smith, P.A. (2002) “Solid-phase microextraction (SPME) for rapid field sampling and analysis by gas chromatography-mass spectrometry (GC-MS). Trends in analytical chemistry, 21,8, 534-543.

. Pawliszyn, J. (1997) Solid Phase Microextraction, Theory and Practice. New York, Wiley-VCH Inc., 97.

. Supelco. (2001) “Control Your “T”s for Better Quantitation with Solid Phase Microextraction (SPME)”. The Reporter, vol 19.7

. Wang, Z., Fingas, M.F. (2003) “ Development of oil hydrocarbon fingerprinting and identification techniques”, Marine Pollution Bulletin. 47. 423-452.

(a)

(b)

(c)

ACKNOWLEDGEMENT

fo i R 1

23

4

SQUARE WAVE CATHODIC STRIPPING VOLTAMMETRIC TECHNIQUE FOR DETERMINATION OF AFLATOXIN B1 IN GROUND NUT SAMPLE

Mohamad Hadzri Yaacob2, Abdull Rahim Hj. Mohd. Yusoff2 and Rahmalan Ahamad2

1School of Health Sciences, USM, 16150 Kubang Krian, Kelantan, Malaysia 2Chemistry Dept., Faculty of Sciences, UTM, 81310 Skudai, Johor, Malaysia

bstract An electroanalytical method has been developed for the detection and determination of the ,3,6a,9a-tetrahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione flatoxin B1, AFB1) by a square wave cathodic stripping voltammetric (SWSV) technique on a

anging mercury drop electrode (HMDE) in aqueous solution with Britton-Robinson Buffer (BRB) at pH 9.0 as the supporting electrolyte. Effect of instrumental parameters such as accumulation potential

), accumulation time (t ), scan rate (ν), square wave frequency, step potential and pulse s, ν of 3750

V/s, frequency of 125 Hz, voltage step of 30 mV and pulse amplitude of 50 mV. Calibration curve ection limit of 0.125 x 10-8 M. Relative standard

eviatio

graphy (HPLC) technique.

arameter peralatan seperti keupayaan p asa ), kadar

a di dalam larutan elusi sampel kacang yang disuntik dengan 3.0 ppb, 9.0 ppb dan 15.0 ppb AFB1 adalah 94.00 +/- 0.67 %, 91.22 +/- 1.56 % dan 92.56 +/- 2.00 % masing-masingnya. Kaedah ini telah digunakan untuk menentukan kandungan AFB1 di dalam ampel kacang tanah selepas proses pengekstraksian dan pembersihan dijalankan. Keputusan yang diperolehi telah dibanding dengan keputusan dari kaedah kromatografi cecair berprestasi tinggi. Keywords: square wave stripping voltammetry, HMDE, aflatoxin B1, ground nut Introduction

flatoxins (AF), the mycotoxin produced mainly by Aspergillus flavus and parasiticus and display strong carcinogenicity [1]. They are dangerous food and contaminants and represent a worldwide threat to public health. AFB1, B2, G1 and G2 and their metabolites M1 and M2 are the most co mon, and of these, AFB1 and AFG1 are observed most frequently in foodstuffs [2]. Of

3] with the order of toxicity is AFB1

A2(ah

(Eacc acc

amplitude were examined. The best condition were found to be Eacc of -0.8 V, tacc of 100mis linear in the range of 0.01 to 0.15 µM with a detd n for a replicate measurements of AFB1 (n = 5) with a concentration of 0.01 µM was 0.83% with a peak potential of -1.30 V (against Ag/AgCl). The recovery values obtained in spiked ground nut elute sample were 94.00 +/- 0.67 % for 3.0 ppb, 91.22 +/- 1.56 % for 9 ppb and 92.56 +/- 2.00 % for 15.0 ppb of AFB1. The method was applied for determination of the AFB1 in ground nut samples after extraction and clean-up steps. The results were compared with that obtained by high performance liquid chromato

Abstrak Satu kaedah elektroanalisis telah dibangunkan untuk mengesan dan menentukan 2,3,6a,9a-tetrahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin B1, AFB1) menggunakan teknik voltammetri perlucutan katodik denyut pembeza di atas elektrod titisan raksa tergantung (HMDE) di dalam larutan akuas dengan larutan penimbal Britton-Robinson (BRB) pada pH 9.0 bertindak sebagai larutan penyokong. Kesan p

engumpulan (Eacc), m pengumpulan (tacc imbasan (ν), frekuensi gelombang bersegi, kenaikan keupayaan dan amplitud denyut telah dikaji. Keadaan terbaik yang diperolehi adalah Eacc; -0.8 V, tacc; 100 s, ν; 3750 mV/s, frekuensi; 125 Hz, kenaikan keupayaan; 30 mV dan amplitud denyut; 50 mV. Keluk kalibrasi adalah linear pada julat di antara 0.01 ke 0.15 µM dengan had pengesan pada 0.125 x 10-8 M. Sisihan piawai relatif untuk 5 kali pengukuran AFB1 dengan kepekatan 0.01 µM ialah 0.83 %. Nilai perolehan semul

s

A

mthese, researches have shown AFB1 (Fig 1) exhibits most toxic [

rresponding address:

hemistry Dept, Faculty of Science, UTM, 1310 Skudai, Johor, Malaysia l: 07-553 4492

2 CoC8te

330

331

O

O

O

O

O

O

AFG1 > AFB2 > AFG2; indicating that the terminal furan moiety of AFB1 is a critical point for etermining the degree of biological activity of this group of mycotoxins [4]. Many countries

including Malaysia have stringent regulatory demands on the level of aflatoxins permitted in imported and traded commodities.

Figure 1 Chemical structure of AFB1

One of the foodstuffs which is most occurrence of AFB1 is ground nut. In Malaysia, the FB1 level in peanut is regulated with maximum level that cannot be greater than 15.0 ppb [5]. everal analytical techniques for quantitative determination of the AFB1 in ground nut have been

proposed such as thin layer chromatograhpy [6], high performance liquid chromatography [7,8,9] and an enzy e-linked immunosorbent assay, ELISA [10], All these methods, however, require specialist equipment operated by skilled personal, expensive instruments and high maintenance cost [11].

ue to all these reasons, a voltammetric technique which is fast, accurate and require low cost equipment [12,13] is proposed. A square wave cathodic stripping voltammetry (SWCV) which is presented in this paper is one of the voltammetric technique that in particularly, has a few advantages compared to other voltammetric technique such as high speed, increased analytical sensitivity and relative insensitivity to the presence of dissolved oxygen [14]. Previous experiment using cyclic voltammetric technique showed that AFB1 reduced at mercury electrode and the reaction is totally irreversible [15]. This work aimed to study and develop a SWSV method for determination of AFB1 at trace levels and to determine this aflatoxin in ground nut samples. No such report has been published regarding this experiment until now.

Experiment Appara

>d

AS

m

D

tus

Square-wave voltammograms were obtained with Metrohm 693 VA Processor coupled with a Metrohm 694 VA stand. Three electrode system was used, consisting of a hanging mercury drop electrode (HMDE) as the working electrode, Ag/AgCl/3 M KCl as the reference electrode and a platinum wire as the auxiliary electrode. A 20 ml capacity measuring cell was used for placing supporting electrolyte and sample analytes. All measurements were carried out at room temperature. All pH measurements were made with Cyberscan pH meter, calibrated with standard buffers at room temperature.

Reagents

AFB1 standard (1 mg per bottle) was purchased from Sigma Co. and was used without further

urification. Stock solution (10 ppm or 3.21 x 10-5 M) in benzene:acetonitrile (98:2) was prepared nd stored in the dark at 14 0C. The diluted solution were prepared daily by using certain volume of tock solution, degassed by nitrogen until dryness and redissolved in Britton-Robinson buffer (BRB) olution at pH 9.0. Britton-Robinson buffer (BRB) solution was prepared from a stock solution 0.04 phosphoric (Merck), boric (Merck) and acetic (Merck) acids; and by adding 1.0 M sodium

ydroxide (Merck) up to pH of 9.0. All solutions were prepared in double distilled dionised water (~ 8M Ω cm). All chemicals were of analytical grade reagents.

rocedure

For voltammetric experiments, 10 ml of BRB solution with pH 9.0 was placed in a oltammetric cell, through which a nitrogen stream was passed for 600 s before recording the

voltammogram. The selected Eacc = - 800 mV was applied during the tacc = 100 s while the solution lapsed, stirring was stopped and the

elected accumulation potential was kept on mercury drop for a rest time (tr = 10 s), after which a otential scan was performed between -1.00 V as initial potential (Ei) and finished at -1.400 V as the al potential (Ef ) by SWSV technique.

Procedure for the determination in ground nut samples

AFB1 was extracted according to the standard procedure developed by Chemistry epartment, Penang Branch, Ministry Of Science, Technology and Innovation, Malaysia [16]. 1ml f the final solution from extraction and clean-up steps in chloroform was pipette into amber bottle, egassed with nitrogen and redissolved in 1ml of BRB solution. 200 ul of this solution was spiked to 10 ml supporting electrolyte in volumetric cell. After that, the general procedure was applied and

oltammogram of sample was recorded. This experiment was followed by a standard addition of 10 pb of AFB1 standard addition and voltammogram of sample with AFB1 standard was recorded.

sing previous differential pulse stripping voltammetry (DPCSV) optimum parameters [17], SWSV as run to determine 0.1 µM AFB1 in BRB pH 9.0. It gave a single reduction signal with peak height p) of 250 nA at peak potential (Ep) of -1.26 V (against Ag/AgCl). The SWSV voltammograms shows proved Ip compared to that obtained by DPCSV where the Ip was increased almost 4 times as

hown in Figure 2.

The effect of the pH of the BRB on the stripping was studied in a pH range of 6 – 13 (Figure ). The Ip increased slowly with increasing pH up to 8.0 followed with sharply increased for pH 8.0 9.0, then decreased in pH 10.0 and continuously decreased in a range of 10 – 13. Thus pH 9.0 was

chosen for the analysis. This result is in aggrement with that found by Smyth et al. (1979) when they erformed polarographic study of AFB1 [18].

Figure 4 shows a dependence of the Ep on pH. Shifting of the Ep towards the negative

irection at higher pH implies that the reduction process takes up hydrogen ions [19]. A double bond aromatic ring conjugates with ketone group, in general, undergoes a reduction at mercury electrode.

ated in Figure 5 as reported by myth et al. (1979) [20].

passMh1 P

v

was kept under stirring. After the accumulation time had espin

Dodinvp Result and discussion

Uw(Iims

3to

p

dinThe suggested mechanism of this reaction in BRB pH 9.0 is illustrS

332

333

050

100150200250

I p (n

A)

300

5 6 7 8 9 10 11 12 13 14

pH of BRB

1.181.2

1.221.241.26 (-

V 1.28)

1.31.321.34

5 6 7 8 9 10 11

pH

Ep

igure 2 Voltammograms of 0.1 uM AFB1 obtained by (a) DPCSV and (b) SWSV techniques. xperimental condition; for DPCSV: Ei = -1.0 V, Ef = -1.4 V, Eacc = -0.6 V, tacc = 80 s, υ = 50 mV/s nd pulse amplitude = 80 mV and for SWSV: E = -1.0 V, E = -1.4 V, E = -0.6 V, t = 80 s,

igure 3 Influence of pH of BRB on the Ip of 0.10 uM AFB1 using SWSV technique. The SWSV strumental parameters are the same as in Figure 2.0.

Figure 4 Relationship between Ep of AFB1 with pH of BRB

FEa i f acc accfrequency = 50 Hz, voltage step = 0.02, amplitude = 50 mV and υ = 1000 mV/s.

Fin

O

OOOO

O

C H 3

2 H 2O

D im e

2H +

r + 2 O H -

22e -

2

C H 3

050

100150200

50

0.2 0.4 0.6 1 1.2 1.4

I p (n

A)

2300

0.8

Ei (-V)

igure 5 Mechanism for reduction of AFB1 at mercury electrode in BRB pH 9.0

ptimisation of condition for the stripping analysis

The voltammetric determination of analytes at trace levels normally involves very small urrent response. For that reason it is important to optimise all those parameters which may have an fluence on the measured current. The effect of Ei , Eacc , tacc, frequency, voltage step and amplitude ere studied. SWSV technique was used with stirring. For this study, 0.1 uM of AFB1 was spiked to supporting electrolyte.

A study of the influence of Ei showing a peak height (Ip) was obtained for Ei = -1.0 V (Figure

). The Ip was slowly decreased for Ei more negative than -1.0 V. This value was chosen for ubsequent studies further optimisation step. Influence of Eacc to Ip of AFB1 was investigated where e Eacc was varied between 0 to -1.4 V. The maximum value of Ip obtained at -0.8 V (366 nA) as

hown in Figure 7. This value was selected for subsequent experiments.

on tacc was studied where tacc was varied from 0 to 160 s. The result is hown in Figure 8 which reveals that there is linearly up to 100s according to equation y = 3.8557x + 1.383 (n=6) with R2 = 0.9936, then it increased rather slowly leveling off at about 140 s. At 160 s, Ip

n for the pre-concentration prior to stripping.

Figure 6 Effect of Ei on the Ip of 0.1 uM AFB1 in BRB pH 9.0

F O

cinwin

6sths

The dependence of Ip

s2decreased which may be due to the electrode saturation [21]. Thus, 100 s was appeared to be aoptimum tacc

334

335

350400

200 (nA)

050

100150

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

I250300

Eacc (-V)

p

00 40 80 120 160 200

50100150200250300

p (n

A)

350

Tacc (s)

I

400450

Figure 7 Effect of Eacc on the Ip of 0.1 uM AFB1 in BRB pH 9.0

Figure

ncy, step potential and pulse amplitude were examined, varying one of them and maintaining constant others. The variable ranges

pulse amplitu . At higher p values the current background increases. Finally, the condition selected were: frequency = 125 Hz, voltage step = 0.03 V and pulse

is 16 time M AFB1 o

8 Effect of tacc on the Ip of 0.1 uM AFB1 in BRB pH 9.0

For other instrumental condition such as square wave freque

were: 25 to 125 Hz for the frequency, 0.01 to 0.04 for the voltage step and 25 – 100 mV for de. Generally, the Ip increase by increasing all of these instrumental parameters [21]otential values the peak width increase; at higher frequency

amplitude = 50 mV (Figures 9 to 11). Under optimised parameters, Ip of AFB1 was 956 nA whichs higher compared to that obtained by DPCSV. Figure 12 shows voltammograms of 0.1 ubtained by SWSV and DPCSV techniques.

336

0

200

0 25 50 75

400

600I p

(nA)

800

1000

100 125 150

Frequency (Hz)

0

200

400

600

800

1000

p (n

A)

1200

0 0.01 0.02 0.03 0.04 0.05

I

Voltage step (V)

0

200

400

600

800

1000

1200

0 0.025 0.05 0.075 0.1 0.125

Amplitude (V)

I p (n

A)

Figure

Figure 11 Dependence of the Ip of AFB1 on SWSV pulse amplitude

Figure 9 Dependence of the Ip of AFB1 on SWSV frequency

10 Dependence of the Ip of AFB1 on SWSV voltage step

337

y = 62.373x + 246.15R2 = 0.9956

0

200

400

600

800

1000

1200

1400

0 5 10 15 20

[AFB1] / 10-8 M

I p (n

A)

Figure 12 Voltammograms of AFB1 obtained by (a) DPCSV and (b) SWSV techniques in BRB pH 9.0. Voltammetric determination of AFB1 and analytical characteristics of the method Using the selected conditions already mentioned, a study was made of the relationship between Ip and concentration. There is a linear relationship in the concentration range 0.01 to 0.15 uM as shown in Figure 13. Limit of detection (LOD) was 0.389 ppb (0.125 x 10-8 M) which was determined by standard addition of low concentration of AFB1 until obtaining the sample response that is significantly difference from blank response [22]. Relative standard deviation (RSD) of the analytical signals at several measurement (n=5) of 0.10 uM AFB1 was 0.83%. Figure 13 Calibration plot of AFB1 in BRB pH 9.0 obtained by SWSV technique. Determination of AFB1 in ground nut samples The proposed method was applied to the analysis of the AFB1 in ground nut samples. Recovery studies were performed by spiked with difference concentration levels of AFB1 standard into eluate of ground nut sample. In this case the concentrations used were 3.0 ppb (0.963 x 10-8 M), 9.0 ppb (2.889 x 10-8 M) and 15.0 ppb (4.815 x 10-8 M). The results of these studies are shown in Table 1. For analysis of AFB1 in ground nut samples, the standard addition method was used in order to eliminate the matrix effects. Figure 14 show voltammograms of real sample together with spiked AFB1 standard. Table 2 listed the content of AFB1 in 6 samples obtained by proposed technique compared with that obtained by HPLC. The results show that there are no significant different of AFB1 content obtained by both techniques.

338

Table 1 Percent recovery of AFB1 spiked in real samples (n=3)

Amount added (ppb)

Amount found (ppb)

Recovery (%) n=3

3.00

9.00

15.00

2.82 +/- 0.02

8.21 +/- 0.14

13.88 +/- 0.30

94.00 +/- 0.67

91.22 +/- 1.56

92.53 +/- 2.00

Figure 14 SWS voltammograms of real sample (b) and spiked AFB1 (c) obtained in BRB pH 9.0 as the supporting electrolyte (a) Table 2 AFB1 content in ground nut samples by proposed technique compared with those obtained by HPLC.

AFB1 content in real sample

No of sample

By SWSV

By HPLC

1 2 3 4 5 6

ND ND ND 9.21

13.92 36.00

ND ND ND 8.25 14.34 36.00

339

Conclusion

A SWSV technique was successfully developed for the determination of AFB1 in ground nut as an alternative method for determination of AFB1 which is sensitive, accurate and fast technique. The results are not significant different with that obtained by accepted technique used for routine analysis of AFB1. Acknowledgement

One of the author would like to thank University Science Malaysia for approving his study

leave and financial support to carry out his further study at Chemistry Dept., UTM. We also indebt to UTM for short term grant (Vot No 75152/2004) and to Chemistry Department, Penang Branch, Ministry of Science, Technology and Innovation for their help in analysis of aflatoxin in ground nut samples using HPLC technique.

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