Simultaneous determination of uric acid, dopamine and ascorbic acid based on poly(bromocresol green) modified glassy carbon electrode

• A poly(bromocresol green) modified glassy carbon electrode was simply prepared.
• The modified electrode was applied for simultaneous determination of UA, DA and AA.
• The modified electrode exhibited good electrocatalytic activity to UA, DA and AA.

A glassy carbon electrode modified with poly(bromocresol green) was prepared by electropolymerization process for simultaneous determination of uric acid, dopamine and ascorbic acid. The interface morphology and structure of poly(bromocresol green) film were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The simultaneous determination of uric acid (UA), dopamine (DA) and ascorbic acid (AA) in 0.1 M phosphate buffer solution (pH 6.0) was carried out by differential pulse voltammetric technique. Under optimum conditions, the results show that the peaks of three species were well separated. The proposed sensor exhibited linear responses to UA, DA and AA in the ranges of 0.5–200, 0.05–10 and 0.5–1000 μM, respectively. Moreover, the poly(bromocresol green) modified electrode has been successfully applied to determine UA, DA and AA in human serum samples and vitamin C tablets.

Electrocatalytic oxidation of UA, DA and AA at poly(bromocresol green) modified glassy carbon electrode were investigated by differential pulse voltammetry. The peak currents of UA, DA and AA increased significantly, and the peak potentials shifted negatively at PBG/GCE, moreover, the peak of DA and AA separate significantly, demonstrating that the proposed methods enhanced the kinetics of the electrochemical process as an efficient promoter.DPVs for 10 μM UA, 0.5 μM DA and 70 μM AA in 0.1 M PBS (pH 6.0) at PBG/GCE (a) and bare GCE (b), and PBG/GCE in blank pH 6.0 PBS (c).Figure optionsDownload as PowerPoint slide