Catalytic oxidation of uric acid at the polyglycine chemically modified electrode and its trace determination

Cyclic voltammetry was undertaken to investigate the electrochemical behavior of uric acid at a polyglycine modified electrode. The modified electrode shows catalytic ability for the oxidation of uric acid, reducing the overpotential by 250 mV in pH 7.0 phosphate buffer solution. The enhanced voltammetric response can be used to determine uric acid. The linear range is between 5.0 x 10(-8) and 4.5 x 10(-6) M with a detection limit as low as 5.0 x 10(-9) M. The relative standard deviation is 1.4% (8 runs) at a concentration of 50 microM uric acid. The catalytic effect of the modified electrode resulted in the voltammetric resolution of the overlapping of uric acid and ascorbic acid. This allows the simultaneous detection of uric acid and ascorbic acid in the same sample.