QUALITY-CONTROL IN THE SPECIATION ANALYSIS OF BUTYLTIN COMPOUNDS IN MARINE BIOLOGICAL SAMPLES BY HYDRIDE GENERATION COLD TRAPPING AND ONLINE QUARTZ FURNACE ATOMIC-ABSORPTION SPECTROMETRY

The determination of tributyltin (TBT) in sea food (mussel, oyster, fish) by a hydride generation-cold trapping-quartz furnace atomic absorption spectrometry procedure has been studied with emphasis on quality control. Large amounts of spiked materials have been prepared and stored either frozen, or frozen after freeze-drying. Extraction of TBT by 0.1 M hydrochloric acid in methanolic solution is efficient (88-96%) for wet samples or freeze-dried samples. It is also efficient with freshly spiked materials. Consumption of sodium borohydride by the matrix makes it necessary to use quite large amounts of reagent to obtain optimal sensitivity. Analysis of a fish-tissue Certified Reference Material seems to indicate a partial debutylation of TBT during transport and/or storage of this material.