Abstract
The polarographic behavior of arsenite at a rotating platinum electrode and the amperometric determination of arsenite with N-bromosuccinimide were investigated. Arsenite gave a peak-shaped oxidation wave, having the half-peak potential at +0.50 V vs. SCE, in an electrolyte solution cotaining 0.1 M KNO3 and Britton-Robinson buffer of pH 5.0. Arsenite did not show any remarkable reduction wave except a cathodic peak at about -0.5 V vs. SCE. The diffusion current of the oxidation wave, measured at +0.60 V, was found to be proportional to the concentration of arsenite from 10-3 to 2×10-5 N within the deviations of ±2.0%. Its temperature coefficient was determined to be 1.9 per cent deg-1 at 25±0.5°C. Arsenite in the low concentration over the range from 10-3 to 8×10-5 N could be determined within an error of ±2.0% by the short-circuit amperometric titration with N-bromosuccinimide by use of a rotating platinum electrode.
