A comparison of automated and traditional methods for the extraction of arsenicals from fish

Abstract

An automated extractor employing accelerated solvent extraction (ASE) has been compared with a traditional sonication method of extraction for the extraction of arsenicals from fish tissue. Four different species of fish and a standard reference material, DORM-2, were subjected to both extraction methods. Arsenicals that were extracted with 50% (m/m) methanol-18 MΩ water were speciated with chromatographic separation and inductively coupled plasma mass spectrometric (ICP-MS) detection. Both extraction methods produced extraction efficiencies of greater than 71% with RSDs on replicates of less than 5.5%. The chromatographic separation employed a PRP-X100 anion exchange column. An ammonium nitrate and ammonium carbonate buffer at pH 9.0 was used to resolve five arsenicals. The speciation data indicates that the predominant species were arsenobetaine and arsenocholine. Two unknown arsenic species were present in most of the samples. The two extraction techniques produce similar relative distribution of arsenobetaine-arsenocholine (AsB-AsC) and dimethylarsinic acid (DMA) with relative area distributions of >95% and <2%, respectively.