Electrocatalytic characteristics of uric acid oxidation at graphite–zeolite-modified electrode doped with iron (III)

A new method is developed for the catalytic oxidation of uric acid at graphite–zeolite-modified electrode doped with iron (III) (Fe3+Y/ZCME). Iron (III) exchanged in zeolite Y act as catalyst to oxidize uric acid. First, the electrochemical behavior of iron (III) incorporated in the zeolite Y-modified electrode was studied. The results illustrate that diffusion controls the ferric/ferrous redox process at the Fe3+Y/ZCME. Then, the behavior of electrocatalytic oxidation reaction for uric acid has researched. The charge transfer coefficient (α) for uric acid was calculated as 0.51. The electrode was employed to study electrocatalytic oxidation of uric acid, using cyclic voltammetry, rotating disk electrode and chronoamperometry as diagnostic techniques. The rate constant for the catalytic reaction (k) was also determined by above methods. The diffusion coefficient of uric acid was 1.54 × 10−6 cm2 s−1. A linear calibration graph is obtained over the uric acid concentration range of 0.1–10.0 mM. Finally, it has been shown that using the Fe3+Y/ZCME, UA can be estimated by amperometry with high sensitivity and good limit of detection by high level of stability of electrode.