Determination of selenium by hydride generation ultraviolet-visible molecular absorption spectrometry with diode-array detection

Abstract

A method for the determination of selenium is described that involves hydrogen selenide generation by reduction with sodium tetrahydroborate(III) and subsequent transfer, using nitrogen as carrier gas, into a flow cell placed in a UV-visible molecular absorption spectrometer with diode-array detection. Quantitative determination is performed at 220 nm, taking 8 s for total hydride generation and measurement. The time required for two determinations is 30 s. The limit of detection obtained was 1.8 µg of Se^IV in a sample volume of 2 ml and the calibration graph is linear from 10 to 150 µg of selenium in a sample of the same volume. The method has been applied to the determination of selenium in a health-care product.