1997 Volume 13 Issue 4 Pages 623-628
Selective determination of selenium(IV) and selenium(VI) in waste water by graphite furnace atomic absorption spectrometry (GFAAS) was developed. The method is based on the reductive coprecipitation of selenium(IV) by L-ascorbic acid or tin(II) chloride and of selenium(VI) by hydrazinium sulfate on a tellurium collector, followed by GFAAS. The ppb levels of selenium(IV) and selenium(VI) were quantitatively coprecipitated with 50-500μg amounts of tellurium collector in 100ml (1M HCl). The selective separation of selenium(IV) from selenium(VI) could be achieved in the presence of 0.2-4.0g of L-ascorbic acid or the optimized amount of tin(II) chloride (molar ratio [SnCl2•2H2O]/[Te(IV)]=50). The proposed methods were successfully applied to real waste-water samples and the standard reference material of river water (JA00032). The detection limit (3σ) was about 0.5ppb of selenium of the water sample.