Application of graphene–SnO2 nanocomposite modified electrode for the sensitive electrochemical detection of dopamine

In this paper a nanocomposite prepared by graphene (GR) and SnO 2 nanosheets was used to modify a N-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode. The presence of GR–SnO 2 nanocomposite on the electrode surface exhibited synergistic effects to improve the electrochemical performance of the modified electrode . Electrochemical behaviors of dopamine (DA) on the electrode were evaluated by cyclic voltammetry and differential pulse voltammetry . The results indicated that the GR–SnO 2 nanocomposite modified electrode displayed high electrocatalytic activity to the oxidation of DA with the increase of the redox peak currents and the decrease of the peak-to-peak separation. Under the selected conditions the oxidation peak current was proportional to the DA concentration in the range from 0.5 to 500.0   μmol/L with a detection limit of 0.13   μmol/L (S/N   =   3). The modified electrode showed excellent selectivity and sensitivity even in the presence of high concentration of uric acid . The proposed method was applied to determine DA content in real samples with satisfactory results.