ABSTRACT
MnO2nanowires-reduced graphene oxide composite (MnO2-RGO) was used to modify glassy carbon electrodes (GCE) and applied for the electrochemical determination of dopamine (DA). The microstructure of MnO2nanowires and MnO2-RGO nanocomposite material was characterized by scanning microscope and X-ray powder diffraction. Then the electrochemical reduction condition for preparing MnO2-RGO/GCE and experimental conditions for determining DA were optimized systematically. The electrochemical behavior of DA on the bare electrode and RGO or MnO2-RGO modified electrodes was also investigated in pH 3.5 phosphate buffer solution (PBS) by cyclic voltammetry. The results shows that the oxidation peaks of ascorbic acid (AA), dopamine (DA) and uric acid (UA) can be well separated and the peak to peak separations were 268 mV (AA-DA) and 128 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of DA were 0.06-1.0 μmol/L and 1.0-80 μmol/L with the detection limit of 1.0 nmol/L (S/N=3). The proposed method has been applied to the determination of dopamine in human blood serum sample with satisfactory results.