A highly active carbon microdisk electrode surface for the determination of uric acid in physiological buffers

To obtain highly active carbon fiber electrodes (CFE) for detection of uric acid by fast scan voltammetry, electrode surfaces were prepared by polishi ng and by electrochemical pretreatment (ECP). The effect of pretreatment pa rameters such as the time of polishing, the activation potential and the co mposisiton of the physiological buffers used in the pretreatment, on electr ode activity in uric acid determinations was investigated. After the ECP, t he background current and the capacitance of the electrode increased in the entire potential window indicating an increase in the apparent electrode a rea. In addition, the background current of the modified CFE was stable eve n after the electrode was exposed to air. Based on the experimental results we postulate that after 30 min of continuos ECP in the potential window fr om -1.0 to 1.5 V vs SCE, formation of nanocracks and edge nanostructures at the surface of the electrode is highly favored yielding a highly active CF E for detection of uric acid in physiological buffers.