Direct electrodeposition of reduced graphene oxide on carbon fiber electrode for simultaneous determination of ascorbic acid, dopamine and uric acid

The electrochemically reduced graphene oxide (ErGO) modified carbon fiber electrode (CFE) was fabricated by a simple electrodeposition method. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) had been used to investigate the electrochemical behavior of ErGO/CFE toward ascorbic acid (AA), dopamine (DA) and uric acid (UA). Compared to the bare CFE, the ErGO/CFE showed higher catalytic activity toward electrochemical oxidation of AA, DA and UA. In the CV curves, three well and distinct peaks with large peak potential separation of 116 mV, 167 mV and 283 mV between AA–DA, DA–UA and AA–UA were observed. In the DPV curves, the corresponding peak potential separations were 198 mV, 163 mV and 361 mV between AA–DA, DA–UA and AA–UA also observed. DPV was used as the analytical technique to acquire the linear calibration curves for AA, DA and UA with the concentration ranges of 8–2016.45 μM, 1.5–224.82 μM, 6–899.3 μM, respectively, in the individual detection of each component. The detection limits were 4.5 μM, 0.77 μM and 2.23 μM for AA, DA and UA indicating that the ErGO/CFE can be achieved with high sensitivity and selectivity for simultaneous determination of these three biomolecules.