Simultaneous determination of dopamine, ascorbic acid and uric acid at electrochemically reduced graphene oxide modified electrode

A facile electrochemical method was applied to prepare electrochemically reduced graphene oxide (ERGO). The morphology and structure of ERGO were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray diffraction (XRD). Compared with the bare glassy carbon electrode (GCE), ERGO modified GCE (ERGO/GCE) exhibits much higher electrocatalytic activities toward the oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) with increasing of peak currents and decreasing of oxidation overpotentials. Differential pulse voltammetry results show that DA, AA and UA could be detected selectively and sensitively at ERGO/GCE with peak-to-peak separation of 240 mV and 130 mV for AA–DA and DA–UA, respectively. The linear ranges for AA, UA and DA are 500–2000 μM, 0.5–60 μM and 0.5–60 μM, respectively. Meanwhile, due to the negligible response to physiological level of AA (0.1 mM), ERGO/GCE could be used for the determination of DA in biological sample with high sensitivity and good selectivity. In addition, the presented method was successfully applied for the simultaneous determination of DA, AA and UA in urine sample with reliable recovery. This work provides a simple and green route to construct graphene-based electrochemical sensor, which is promising for the simultaneous determination of DA, AA and UA.