Determination of 6 Arsenic Species in Livestock Products by HPLC-ICP-MS Combined with Accelerated Solvent Extraction

A method of HPLC-ICP-MS was applied to the determination of methyl arsenic, dimethyl arsenic, arsenic(Ⅲ), arsenic(Ⅴ), arsenic choline and arsenic betaine in livestock products. About 3.0 g of the sample pulverized by a tissue pulverizer was added into a stainless steel extraction tank, and 6 g of quartz sand was added. The mixture was stirred uniformly, and methanol (2+1) solution was used as extraction solvent to carry out accelerated solvent extraction. After the extraction was completed, the extract was made up to 100 mL with methanol (2+1) solution, and filtered through a 0.45 μm filter membrane. The 6 arsenic species were seperated on a Dionex IonPac AS-17 column (250 mm×4.0 mm, 10 μm), with 20 mmol·L^-1 NH₄HCO₃ solution as mobile phase for elution at a flow rate of 1.0 mL·min^-1. ICP-MS was used to determine the 6 arsenic species in the eluate. The result showed that linear relationships were found between response intensity and mass concentration of the 6 arsenic species in the same range of 0.5-50.0 μg·L^-1, with detection limits (3S/N) in the range 0.15-0.24 μg·kg^-1. Values of recovery obtained by standard addition method were in the range of 86.0%-108%, and RSDs (n=6) were in the range of 2.6%-3.9%.