Electrocatalytic Oxidation of Uric Acid at Cysteine Modified Glassy Carbon Electrode

ABSTRACT

The electrochemical behavior of uric acid at a cysteine modified glassy electrode has been studied by cyclic voltammetry(CV) and differential pulse voltammetry (DPV). The results indicated that the modified electrode exhibited efficient electrocatalytic oxidation for uric acid. The anodic overpotential was reduced nearly 200mV compared with the result obtained at a bare electrode. The diffusion coefficient of uric acid in solution and the rate constant for the catalytic reaction were calculated by a Koutecky-Levich plot. A good linear response to uric acid in the range of 7.0x10⁻⁷ to 3.0x10⁻⁴ mol/L was obtained. The detection limit was 3.7x10⁻⁷ mol/L. High stability and good selectivity made possible applications to in-vivo measurements.

Keywords::

• uric acid
• cysteine
• chemically modified electrode
• voltammetry