Determination of total tin in sediments by graphite furnace atomic absorption spectrometry

A method for the determination of total tin in sediments containing organotin compounds by graphite furnace atomic absorption spectrometry has 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 dissolved with 3 ml nitric acid. The solution was made up to 50 ml in a polypropylene measuring flask. 20 μl of the sample solution and 10 μl of nickel solution (20 g Nil-1) were injected onto a platform in a graphite tube. The stabilized temperature platform furnace (STPF) technique was applied. Nickel and palladium were good as matrix modifiers. Diverse elements had no effect, at least up to the respective concentration 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 aluminium gave a -5% error. Accordingly, when a sample contained over 20% aluminium, aluminium equivalent to 20% of the sample, was added for preparation of calibration curves. The recoveries of organotin compounds (TBT, 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 (3σ) was 54 pg, that is, 0.27 μgg-1 of sample.