Determination of total tin in shellfish samples by graphite-furnace AAS.

An accurate and sensitive analytical method for total tin in shellfish samples has been established.Graphite-furnace atomic absorption with a highly efficient atomization method was examined.Good results were obtained by applying a matrix modifier of nickel addition, high-speed temperature rising of the graphite tube, an area-integral measurement and an AC Zeeman-effect background correction.The direct analysis of a sample solution and high sensitivity were achieved by this method.Blue mussel samples collected from Tokyo Bay(Daikoku and Ukishima)and the coast of Kujukuri were analyzed.Homogenized samples were freezedried.After nitric acid(10ml), hydrofluoric acid(5ml)and perchloric acid(5ml)were added to a dried sample(0.5g), it was decomposed by heating.The sample solution was vaporized to dryness and the residues was dissolved with nitric acid(3ml).The sample solution(20μl)and a nickel solution(20gl-1;5μl)were injected onto a platform in a graphite tube and measured by graphite-furnace atomic-absorption spectrometry.The total tin concentration of mussel was 0.5ppm(Daikoku), 0.8ppm(Ukishima), and <0.1ppm(Kujyukuri).A certified reference material(NIES No.11)was analyzed, and a good result was obtained.