Selenium inorganic speciation in beers using MSFIA-HG-AFS system after multivariate optimization

In this work, the use of a multisyringe flow injection analysis coupled to hydride generation atomic fluorescence spectrometry (MSFIA-HG-AFS) for inorganic selenium chemical speciation was proposed. A Doehlert design was applied to optimize the experimental conditions for hydride generation (NaBH₄ and HCl concentrations). The limits of quantification (LoQ) obtained were 0.07 µg L^-1, for total inorganic Se, and 0.08 µg L^-1, for Se(IV). Accuracy and precision of the proposed analytical method were evaluated through analysis of standard reference material and addition and recovery tests. The optimized method was applied to analyses of eight samples of beer, produced in Spain, obtaining concentrations for Se(IV) (<0.08 - 0.46 ± 0.01 µg L^-1), total inorganic Se (0.47 ± 0.01 - 3.04 ± 0.62 µg L^-1) and Se(VI) (0.06 ± 0.01 - 3.00 ± 0.59 µg L^-1). The proposed analytical method was accurate, precise and sensitivity for determination of selenium species in beer samples.