Electrochemical Oxidation and Voltammetric Determination of Basic Brown G at a Carbon Paste Electrode

The electrochemical oxidation behavior and oxidation mechanism of Basic Brown G (BBG) were studied at a carbon paste electrode (CPE) for the first time. In pH 11.0 phosphate buffer, two irreversible oxidation peaks of BBG at 0.39 V and 0.78 V (versus SCE) were observed, which were both two-electron and two-proton process with diffusion character. The two peaks were assigned to the oxidation of 1, and 1’-phenylamine groups and the further oxidation of the oxidation products in the BBG molecule. The diffusion coefficient of BBG was assessed to be 8.7×10 -5 cm 2 s -1 . A square wave voltammetric method was proposed for the determination of BBG. The peak current of the oxidation peak of BBG was linear with its concentration in the ranges from 0.004 to 0.2 μM and 0.2 to 2.0 μM, with a detection limit of 1.2 nM (3S/N). The proposed method was employed to the quantification of BBG in water samples.