DETERMINATION OF TOTAL TIN IN SEDIMENTS B Y GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

A method for the determination of total tin in sediments containing or ganotin compounds by graphite furnace atomic absorption spectrometry h as been developed. 0.5 g sample was decomposed with 3 ml HNO3, 5 ml HF , and 5 ml HClO4, the solution vaporized to dryness and the residues d issolved with 3 ml nitric acid. The solution was made up to 50 ml in a polypropylene measuring flask. 20 mu l of the sample solution and 10 mu l of nickel solution (20 g Nil(-1)) were injected onto a platform i n a graphite tube. The stabilized temperature platform furnace (STPF) technique was applied. Nickel and palladium were good as matrix modifi ers. Diverse elements had no effect, at least up to the respective con centration of Fe (10% in a sample), Ca(5%), Mg(3%), K(1%), Mn(1%), P(1 %), and Ti(1%). Aluminium was tolerated up to 10%, but 15% of aluminiu m gave a -5% error. Accordingly, when a sample contained over 20% alum inium, aluminium equivalent to 20% of the sample, was added for prepar ation of calibration curves. The recoveries of organotin compounds (TB T, DBT, MBT, TPT, DPT, MPT) were almost 100%. The values determined in standard reference materials showed good agreement with the certified values. The limit of detection (3 sigma) was 54 pg, that is, 0.27 mu g g(-1) of sample.