Arsenic speciation in fish on the market

Abstract

Arsenic speciation in fish samples on the market was analyzed using gradient anion exchange high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICPMS) detection. Freeze-dried samples were extracted by methanol and water mixture (8:2v/v) with a high-speed Soxhlet system; the concentration of arsenobetaine (AsB), dimethylarsinic acid (DMAA), monomethylarsonic acid (MMAA), arsenate (As(V)) and arsenite (As(Ⅲ)) in the extract were then determined using HPLC-ICPMS. The method for determining arsenobetaine concentration was confirmed using standard reference material (SRM) of BCR 627 (tuna fish) and DORM-2 (dogfish muscle); recovery rates were 95 and 90%, respectively. The arsenic compounds in 60 market-ready fish muscle samples were investigated. The predominant arsenic compound found in samples was AsB. Arsenate was detected in low concentrations (ranged in 0.02-0.34 mg/kg As for fresh weight), whereas DMAA, MMAA and arsenite content were undetectable. Average AsB content in cephalopods, small fish and large fish were 5.42, 1.57 and 1.54 mg/kg As (fresh weight), respectively. The weekly intake of As was calculated based on the consumption of fish by Taiwanese residents. The calculated results demonstrated that the intake is 30.6 μg/kg (total As) body weight/week, higher than the acceptable weekly intake of 15 μg/kg body weight/week for inorganic arsenic that was suggested by WHO. However, around 87% of As in fish muscle was AsB. AsB is non-toxic and non-carcinogenic to humans, and is rapidly excreted after ingestion. Therefore, intake of fish muscle is low risk based on investigation results.