Interference-free determination of selenium(IV) by capillary gas chromatography–microwave-induced plasma atomic emission spectrometry after volatilization with sodium tetraethylborate

Abstract

Quantitative volatilization of Se^IV from aqueous solutions by its reaction with sodium tetraethylborate was developed and was followed by the determination of selenium by capillary gas chromatography–microwave-induced plasma atomic emission sepectrometry. An essential increase in the selectivity of the determination was observed compared with the commonly used gas chromatography–hydride generation atomic absorption spectrometry. The influence of the medium on the efficiency of the reaction was studied. Hydrochloric acid of 4 mol l^–1 was necessary to achieve maximum efficiency in the derivatization. The possibility of applying the derivatizating reaction for the selective determination of Se^IV in presence of Se^VI is discussed. A microwave-induced plasma was used as an atomizer. A detection limit of 8 ng l^–1(for a 5 ml sample) in a fully automated system was achieved. The method was applied to the determination of selenium in natural water samples.