Differential-pulse adsorptive stripping voltammetry of 3-(4,5-dimethyl-2-thiazolylazo)-2,6-diaminopyridine

Abstract

The surface-active properties of the azo dye 3-(4,5-dimethyl-2-thiazolylazo)-2,6-diaminopyridine (DMTADAP) allowed its determination at sub-nanomolar levels by differential-pulse adsorptive stripping voltammetry at a hanging mercury drop electrode. The influence of electrolyte, pH, accumulation potential, accumulation time and concentration on the adsorptive stripping signals was studied. A determination limit below 8 × 10^–10M was obtained for an accumulation time of 4 min in phosphate buffer at pH 7.0. The reproducibility of the determination (at the 1.6 × 10^–8M level) expressed in terms of relative standard deviation was 3%(for five determinations).