Speciation: Determination of methylmercury in fish samples with HPLC-ICP-MS

Abstract

Two mercury species in National Research Council of Canada Certified Reference Material (NRCC CRM) (a) TORT-2 and (b) DORM-2 can be determined using high performance liquid chromatography (HPLC) in conjunction with inductively coupled plasma mass spectrometry (ICP-MS). A non-aggressive extraction method was employed to maintain the integrity of the species in the samples. Chromatographic separation of mercury species could be achieved in 6 minutes with a reversed phase column using 0.1% of L-cysteine as the mobile phase. The limit of detection for this method is 0.5 ppb (μg/kg), sufficient to determine low levels of mercury in fish samples. The accuracy of the method was evaluated by analyzing marine biological certified reference materials (TORT-2 and DORM-2). The proposed method was then successfully applied to the determination of methylmercury compounds in "Ikan Kem-bung", a popular local fish for grilling, also known as Indian Mackerel.