Evaluation of atomic fluorescence and atomic absorption spectrometric techniques for the determination of arsenic in wine and beer by direct hydride generation sample introduction

Abstract

A simple and rapid flow injection-arsenic hydride generation-atomic fluorescence spectrometric (FI-HG-AFS) method has been optimized for the direct determination of arsenic in untreated samples of beer and wine. Several aspects were evaluated: concentration of HCl and NaBH ₄ , argon and hydrogen flow-rates and effect of oxidation state on the analytical signal. The optimum conditions selected were 6 m HCl and 0.5% (m/v) NaBH ₄ and 6 m HCl and 1% (m/v) NaBH ₄ to determine total arsenic contents of different brands of beer and wine, respectively. The accuracy of the method was evaluated by comparing the results obtained with those provided for three mineralization procedures: HNO ₃ -H ₂ O ₂ , H ₂ SO ₄ -HNO ₃ -HClO ₄ and Mg(NO ₃ ) ₂ -MgO mixtures. The results obtained showed good agreement between the conventional digestion procedures and the direct determination of arsenic in the untreated samples. The method enables the determination of arsenic to be made in untreated samples with detection limits of 0.3 and 0.5 µg L ^–1 for beer and wine, respectively.