EXTRACTION AND DETERMINATION OF BUTYLTIN COMPOUNDS IN SHELLFISH BY HYDRIDE GENERATION GAS-CHROMATOGRAPHY QUARTZ FURNACE ATOMIC-ABSORPTION SPECTROMETRY

The method described involves the conversion of butyltin compounds ext racted from shellfish into volatile hydrides by sodium tetrahydroborat e, cryogenic trapping and selective volatilization followed by on-line quartz furnace atomic absorption spectrometric detection. Several sam ple pretreatment procedures were compared with emphasis on their accur acy, reproducibility and respect for the speciation of tin. Digestion with 0.083 M HCl in 16.7% methanol under sonication for 1 h- is propos ed. The recoveries of mono-, di- and tributyltin compounds from spiked mussel and oyster samples ranged from 96 to 99% with low degradation of butyltins (< 9%). Detection limits were in the 2-3 ng Sn g(-1) (wet weight) range. The method was applied to wild and commercial samples of oysters, mussels and scallops and fairly high concentrations of but yltin compounds were measured.