Selective detection of dopamine based on the unique property of gold nanofilm

Gold nanofilm, with a nanoporous morphology, was found to have the unique property to catalyze the oxidization of ascorbic acid (AA) and dopamine (DA), resulting in the improved electrochemical behavior of the two species and a negative shift of the oxidization potential of AA for about 300 mV. The catalytic oxidization of gold nanofilm to AA is mainly ascribed to its high surface energy, while the enhanced electron transfer ability of DA on the gold nanofilm is attributed to the strong interaction between DA and the electrode surface. Based on the peak separation of DA and AA, selective detection of DA was achieved on the gold nanofilm modified electrode. Differential pulse voltammetry (DPV) techniques and cyclic voltammetry (CV) were used to investigate the electrochemical behavior of AA and DA on the surface of the electrode. Afterwards, the obtained gold nanofilm was applied in selective detection of dopamine (DA) in the presence of ascorbic acid (AA) at near neutral pH by DPV in the optimized conditions. The linear range for DA was 1.5–27.5 μM. The electrode also shows good stability during detection.