Determination of the different oxidation states of As and Sb by a new electrochemical hydride generator coupled with atomic fluorescence spectrometry

A novel disk electrochemical hydride generator has been developed for the determination of As and Sb. Compared with the traditional thin-layer cell, the disk cell combined the advantages of quick assembly and easy operation. This electrochemical system for hydride generation in neutral buffer solutions has been studied for analytical usefulness in coupling with atomic fluorescence spectrometry. It was found that the use of neutral phosphate buffer solution could markedly increase the fluorescence intensity of As(III) and Sb(III) and reduce the impact of cathode erosion on the stability of signal intensity. At the same time, the fluorescence intensity of As(V) and Sb(V) were almost suppressed totally. The detection limits (3σ) of 0.031 μg L⁻¹ As(III) and 0.026 μg L⁻¹ Sb(III) in aqueous solutions were obtained, respectively. The precisions (n = 11) for 20 μg L⁻¹ As(III) and Sb(III) were 2.0% and 2.7%, respectively. The method was successfully applied for determination of different oxidation states of As and Sb in environmental samples.