A multilayer gold nanoparticle-polydopamine hybrid membrane-modified indium tin oxide electrode for selective sensing of dopamine in the present of ascorbic acid

In this paper, dopamine (DA) ionic states in different pH solutions and corresponding electrochemical reaction characteristics on indium tin oxide (ITO) electrodes were discussed in detail. Polydopamine (PDA) and gold nanoparticles (AuNPs) have been used to modify ITO electrodes for selective sensing of DA in the present of ascorbic acid (AA). The impedance of PDA membranes and the catalysis of AuNPs on the interfacial properties of the modified electrodes were studied tentatively. Experiments show that a three-layer AuNP-PDA hybrid membrane-modified ITO electrode has an excellent property in DA detection without being interfered by the existence of AA. The sensitivity of DA detection was obtained to be 0.300 μA/μM with a detection limit of 0.06 μM ( S / N = 3) in chronoamperometry measurement. The application of the electrode was verified in real sample analysis with both differential pulse voltammetry and chronoamperometry measurements.