A FLOWING ELECTROLYTIC HYDRIDE GENERATOR FOR CONTINUOUS SAMPLE INTRODUCTION IN ATOMIC SPECTROMETRY

Hydride generation is a useful technique for sample introduction in atomic spectrometry. Apparatus utilizing the chemical reduction of aqueous As, Se, Sb, Te and Pb are in common use and commercially available. An alternate method of hydride generation is electrolytic reduction. This method requires fewer reagents, reducing the potential risk of sample contamination. In this study, the construction and evaluation of a new flowing electrolytic hydride generator for sample introduction in atomic spectrometry is described. The effectiveness of several possible cathode materials and electrolytes is compared. Flame atomic absorption spectrometry was used to detect As, Se and Sb in aqueous solutions after conversion to AsH3, H2Se and SbH3. Sensitivity increases of 11-18 times over pneumatic solution nebulization were realized. Also, inductively coupled plasma atomic emission spectrometry (ICP-AES) was combined with this new type of hydride generator for the detection and quantitation of As and Se in aqueous solutions. Detection limits by ICP-AES were 0.7 mu g/ml and 3 mu g/ml for As and Se, respectively. In addition, the effects of several possible concomitants on the production of H2Se and AsH3 were examined.