INTERFERENCE-FREE DETERMINATION OF SELENIUM(IV) BY CAPILLARY GAS CHROMATOGRAPHY-MICROWAVE-INDUCED PLASMA-ATOMIC EMISSION-SPECTROMETRY AFTERVOLATILIZATION WITH SODIUM TETRAETHYLBORATE

Quantitative volatilization of Se-IV from aqueous solutions by its rea ction with sodium tetraethylborate was developed and was followed by t he determination of selenium by capillary gas chromatography-microwave -induced plasma atomic emission sepectrometry. An essential increase i n 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 rea ction was studied. Hydrochloric acid of 4 mol l(-1) was necessary to a chieve maximum efficiency in the derivatization. The possibility of ap plying the derivatizating reaction for the selective determination of Se-IV in presence of Se-VI is discussed. A microwave-induced plasma wa s used as an atomizer. A detection limit of 8 ng l(-1) (for a 5 ml sam ple) in a fully automated system was achieved. The method was applied to the determination of selenium in natural water samples.