Analytical Sciences

Determination of Arsenic Species in Marine Samples by HPLC-ICP-MS

Shizuko HIRATA,* Hideki TOSHIMITSU,** and Masato AIHARA**

*Biomass Technology Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 2-2-2 Hiro-suehiro, Kure 737-0197, Japan
**Graduate School of Kinki University, 1 Takaya-Uminobe, Higashi-Hiroshima 739-2116, Japan

Arsenic speciation analysis in marine samples was performed using high performance liquid chromatography (HPLC) with ICP-MS detection. The separation of eight arsenic species viz. arsenite (As^III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenate (As^V), arsenobetaine, trimethylarsine oxide (TMAO), arsenocholine and tetramethylarsonium ion (TeMAs) was achieved on a Shiseido Capcell Pak C₁₈ column by using an isocratic eluent (pH 3.0), in which condition As^III and MMA were co-eluted. The entire separation was accomplished in 15 min. The detection limits for 8 arsenic species by HPLC/ICP-MS were in the range of 0.02 - 0.10 µg L^-1 based on 3 σ of blank response (n = 9). The precision was calculated to be 3.1 - 7.3% (RSD) for all eight species. The method then successfully applied to several marine samples e.g., oyster, scallop, fish, and shrimps. For the extraction of arsenic species from seafood products, the low power microwave digestion was employed. The extraction efficiency was in the range of 52.9 - 112.3%. Total arsenic concentrations were analyzed by using the microwave acid digestion. The total arsenics in the certified reference materials (DORM-2 and TORT-2) were analyzed and agreed with the certified values. The concentrations of arsenics in marine samples were in the range 6.6 - 35.1 µg g^-1.

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