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

An accurate and sensitive analytical method for total tin in shellfish samp les has been established. Graphite-furnace atomic absorption with a highly efficient atomization method was examined. Good results were obtained by ap plying a matrix modifier of nickel addition, highspeed temperature rising o f the graphite tube, an area-integral measurement and an AC Zeeman-effect b ackground correction. The direct analysis of a sample solution and high sen sitivity were achieved by this method. Blue mussel samples collected from T okyo Bay (Daikoku and Ukishima) and the coast of Kujukuri were analyzed. Ho mogenized Samples were freeze-dried. After nitric acid (10 ml), hydrofluori c acid (5 ml) and perchloric acid (5 ml) were added to a dried sample (0.5 g), it was decomposed by heating. The sample solution was vaporized to dryn ess and the residues was dissolved with nitric acid (3 ml). The sample solu tion (20 mul ) and a nickel solution (20 g 1(-1); 5 mul) were injected onto a platform in a graphite tube and measured by graphite-furnace atomic-abso rption spectrometry. The total tin concentration of mussel was 0.5 ppm (Dai koku), 0.8 ppm (Ukishima), and <0.1 ppm (Kujyukuri). A certified reference material (NIES No.11) was analyzed, and a good result was obtained.