Arsenic Speciation in Drinking Tea Samples by Hydride Generation Atomic Fluorescence Spectrometry

Abstract

A simple, low cost and fast speciation method has been developed for the arsenic speciation by hydride generation atomic fluorescence spectrometry (HG-AFS). The contents of arsenic(III) and arsenic(V) was calculated by solving the simultaneous equations obtained at two different experimental conditions, i.e., in the citric acid medium and thiourea-ascorbic acid medium. The total arsenic content was detected after the sample was digested with HNO₃ and H₂O₂ and prepared in thiourea-ascorbic acid medium. The content of the organic arsenic was calculated by subtracting the amount of inorganic arsenic from the total amount of arsenic. The detection limits of this method were 7.0 × 10^-2 μg L^-1 for As (III) and 9.5 × 10^-2 μg L^-1 for total inorganic arsenic, respectively. This method was applied to the arsenic speciation in six types of Chinese drinking tea without chromatographic and electrophoretic separation.