Speciation of arsenic in fish tissue using microwave-assisted extraction followed by HPLC-ICP-MS

The use of microwave-assisted extraction for the extraction of arsenic spec ies from fish tissue is described. Quantitative extraction of arsenic from spiny dogfish muscle (CRM, DORM-2) was achieved using methanol-water (80 20, v/v) with microwave heating at 65 degrees C in a closed-vessel microwav e system. Extractions were performed with a variety of solvents including w ater, two different methanol-water mixtures, and a 5% tetramethylammonium h ydroxide solution. Extracted arsenic species were separated using both ion- exchange and ion-pair chromatography with ICP-MS detection. The DORM-2 alon g with three different varieties of fish purchased from a local market were analyzed for arsenic. In all samples, the majority of arsenic present was in the form of arsenobetaine, a nontoxic arsenic species.