Determination of selenium in water and soil by hydride generation atomic absorption spectrometry using solid reagents.

A hydride generation method for the determination of traces of selenium at ngmL(-1) concentration ranges has been introduced using a solid mixture of tartaric acid and sodium tetrahydroborate. Atomic absorption spectrometry (AAS) has been used as the detection system. Several parameters such as the ratio of tartaric acid to sodium tetrahydroborate, type and amount of acid, and the reaction temperature were optimized by using 640ngmL(-1) (16ng per 25muL) of Se(IV) standard solution. The calibration curve was linear from 20 to 1200ngmL(-1) (0.5-30ng Se(IV) per 25muL). The relative standard deviation (%R.S.D.) of the determination was 1.93% and the detection limit was 10.6ngmL(-1) (265pg per 25muL) of Se(IV). The reliability of the method was checked using different types of environmental samples, such as several types of water, a sample of soil and also in a kind of calcium phosphate sample by standard addition method. For conversion of Se(VI) present in real samples to Se(IV), l-cysteine was added to NaBH(4) and tartaric acid mixture. The results showed good agreement between this method and other hydride generation techniques.