Graphene-Modified Electrode for the Selective Determination of Uric Acid Under Coexistence of Dopamine and Ascorbic Acid

A graphene-modified electrode for selective determination of uric acid was prepared. The electrochemical behaviours of uric acid at the graphene-modified electrode was investigated by cyclic voltammetry and the results showed that the graphene film on electrode exhibited excellent electrocatalytic activity for the electrochemical oxidation of uric acid in phosphate buffer solution (pH 4.0). Using the graphene-modified electrode, uric acid under coexistence of dopamine and ascorbic acid was successfully determined with good peak separation. The values of linearity range, correlation coefficient and limit of detection for uric acid were 2.00x10(-6) to 1.20x10(-4) mol/L, 0.9975 and 6.00x10(-7) mol/L respectively. The graphene-modified electrode is of excellent sensitivity, selectivity and stability, and has been successfully used for determination of uric acid in human urine.