Preparation of Cu(2)O-Reduced Graphene Nanocomposite Modified Electrodes towards Ultrasensitive Dopamine Detection

Cu(2)O-reduced graphene oxide nanocomposite (Cu(2)O-RGO) was used to modify glassy carbon electrodes (GCE), and applied for the determination of dopamine (DA). The microstructure of Cu(2)O-RGO nanocomposite material was characterized by scanning electron microscope. Then the electrochemical reduction condition for preparing Cu(2)O-RGO/GCE and experimental conditions for determining DA were further optimized. The electrochemical behaviors of DA on the bare electrode, RGO- and Cu(2)O-RGO-modified electrodes were also investigated using cyclic voltammetry in phosphate-buffered saline solution (PBS, pH 3.5). The results show that the oxidation peaks of ascorbic acid (AA), dopamine (DA), and uric acid (UA) could be well separated and the peak-to-peak separations are 204 mV (AA-DA) and 144 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of 1 × 10(−8) mol/L~1 × 10(−6) mol/L and 1 × 10(−6) mol/L~8 × 10(−5) mol/L with the detection limit 6.0 × 10(−9) mol/L (S/N = 3). The proposed Cu(2)O-RGO/GCE was further applied to the determination of DA in dopamine hydrochloride injections with satisfactory results.