Sains Malaysiana 41(12)(2012): 1557–1564

 

Comparison of Microwave Assisted Acid Digestion Methods for ICP-MS

Determination of Total Arsenic in Fish Tissue

(Perbandingan Kaedah Penghadaman Asid dengan Bantuan Mikrogelombangbagi Penentuan Jumlah Arsenik dalam Tisu Ikan Menggunakan ICP-MS)

 

S. Ghanthimathi*

National Public Health Laboratory, Lot 1853, Kampong Melayu Sg buloh

47000 Sungai Buloh, Selangor Darul Ehsan, Malaysia

 

Aminah Abdullah

Pusat Pengajian Sains Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia,43600 Bangi, Selangor Darul Ehsan, Malaysia

 

S. Salmijah.

Pusat Pengajian Biosains dan Bioteknologi, Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia,43600 Bangi, Selangor Darul Ehsan, Malaysia

 

  T. Ujang

Centre for Public health Science, Queensland Health Forensics and Scientific Services, 39 Kessels Road, Cooper Plains, Qld 4108, Australia

 

A. Nurul Izzah

Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia

 

Received: 25 May 2012 / Accepted: 1 August 2012

 

ABSTRACT

 

Fish is one of the most important sources of arsenic exposure in human diet and the Food Safety and Quality Division, Ministry of Health since 2007 has required routine monitoring of total arsenic in seafoods such as fish. This study describes an improved extraction method of total arsenic in fish using microwave assisted acid digestion procedure before being analysed by inductively coupled plasma mass spectrometry (ICP-MS). The parameters studied were pre-treatment of sample, digestion temperature, time programme and the chemicals (HNO₃/H₂O₂) used. Arsenic contents in fish samples under these conditions were compared using the standards additions technique. Microwave assisted acid digestion method with a combination of ultrapure concentrated nitric acid (HNO₃) to concentrated hydrogen peroxide (H₂O₂) at a ratio of 7 mL: 1 mL, run time of 25 min and digestion temperature of 200°C with no pre-treatment was found to have recovery of 100.7% as compared to other digestion procedure where the recovery were 115.5, 111.6 and 101.8%. Validation using certified reference material (CRM) of fish tissue (DORM-3) showed a recovery of 101.4 ± 2.5% for total arsenic from the CRM.

 

Keywords: Arsenic; certified reference material; fish; inductively coupled plasma mass spectrometry; microwave assisted acid digestion

 

ABSTRAK

 

Ikan adalah salah satu daripada sumber yang paling penting bagi pendedahan arsenik dalam diet manusia dan sejak 2007 Bahagian Keselamatan dan Kualiti Makanan, Kementerian Kesihatan telah menjalankan pemantauan rutin bagi jumlah arsenik dalam makanan laut seperti ikan. Kajian ini menerangkan kaedah pengekstrakan yang diperbaiki bagi jumlah arsenik dalam ikan dengan menggunakan prosedur penghadaman mikrogelombang dengan bantuan asid sebelum dianalisis dengan menggunakan spektrometri jisim plasma gandingan aruhan (ICP-MS). Parameter yang dikaji adalah pra-perlakuan sampel, suhu penghadaman, program masa dan bahan kimia (HNO₃/ H₂O₂). Kandungan jumlah arsenik dalam sampel ikan dalam keadaan tersebut dibandingkan dengan menentukan perolehan penambahan bahan piawai jumlah arsenik. Kaedah mikrogelombang dengan bantuan asid dengan gabungan asid nitrik (HNO₃) serta hidrogen peroksida pekat (H₂O₂) tulen pada nisbah 7 mL:1 mL dengan masa analisis selama 25 min dan suhu penghadaman 200°C serta tiada pra-perlakuan sampel, didapati mempunyai nilai perolehan 100.7% berbandingkan dengan kaedah lain dengan nilai perolehannya adalah 115.5, 111.6 dan 101.8%. Validasi telah dijalankan dengan menggunakan bahan rujukan yang disahkan atau (CRM) tisu ikan (DORM-3) menunjukkan perolehan 101.4 ± 2.5% bagi jumlah arsenik dari CRM.

 

Kata kunci: Arsenik; bahan rujukan yang disahkan; ikan; mikrogelombang dengan bantuan asid; spektrometri jisim-plasma gandingan aruhan

 

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*Corresponding author; email: ghanthimathi@yahoo.com