Determination of Selenium(IV) by Catalytic Stripping Voltammetry with an in situ Plated Bismuth-film Electrode

Abstract

A very sensitive and simple method is presented for the determination of Se(IV) by Osteryang square-wave cathodic stripping voltammery (OSWCSV). The method is based on the reduction of Se(IV) with Bi(III) onto an edge-plane type of pyrolytic graphite substrate, followed by a cathodic potential scan. OSWCSV studies indicate that the reduced selenium produced a distinct catalytic hydrogen wave at -1150 mV vs. Ag/AgCl. The peak height of the catalytic hydrogen wave was directly proportional to the initial Se(IV) concentration in the ranges of 0.1 - 1.0 and 1.0 - 20.0 µg L^-1 (correlation coefficients 0.9800 and 0.9901, respectively) when the optimized parameters were used. A 3σ detection limit of 0.025 µg L^-10 Se(IV) was obtained at 30 s deposition time. The relative standard deviation was 4.0% on replicate runs (n = 12) for the determinations of 0.10 µg L^-1 Se(IV). Analytical results of natural water samples demonstrate that the proposed method is applicable to speciation analysis of Se(IV) and Se(VI).