A study on arsenic speciation analysis in animal origin seafood

Abstract

To develop a method for determining arsenobetaine (AsB), arsenite (AsIII), arsenate (AsV), Monomethylarsonic acid (MMA) and Dimethylarsenic acid (DMA) with liquid chromatography (LC), on-line UV-decomposition (UV), hydride generation (HG) and atomic fluorescence spectrometry (AFS) in animal origin seafood samples. Arsenic compounds were extracted in an ultrasonic bath with methanol-water (9:1) solvent from the animal origin seafood samples. The extracts were evaporated with N2 and dissolved in water. The solvent was extracted by hexane to remove lipids. And then, the aqueous solution was diluted to 10 ml. The extracts were filtered before analysis by LC-AFS. The mobile phase consisted of 0.5 mmol/L NH4H2PO4 (pH 9.0) and 20 mmol/L NH4H2PO4 (pH 6.0). Arsenic species were separated with an anion exchange column Hamilton PRPX-100 and gradient elution, detected by LC-UV-HG-AFS. The established separation condition could achieve a better separation for five arsenic species. Detection Limits (LOD) were ranged from 0.0025 to 0.0032 mg/L, AsB was the predominant arsenic species in the animal origin seafood samples. AsIII and DMA were detected in certain shellfish samples at trace level. The accuracy of total arsenic measurement was tested by the analysis of NBS 1566 (Oyster Tissue). The accuracy of arsenic species measurement was tested by the analysis of BCR 627 (Tuna Fish). The data were tallied with the certified value. Arsenic species were specifically detected by LC-UV-HG-AFS in the animal origin seafood samples.