A highly sensitive electrode modified with graphene, gold nanoparticles, and molecularly imprinted over-oxidized polypyrrole for electrochemical determination of dopamine

A glassy carbon electrode (GCE), modified with graphene (Gr) films, molecularly imprinted (MIP) over-oxidized polypyrrole (OPPy), and electrochemically de posited gold nanoparticles (AuNP) was used for rapid detection of dopamine (DA). The as-prepared electrode (AuNP/Gr/OPPy-MIP/GCE) was characterized by Raman spectroscopy and atomic force microscopy (AFM). Electrochemical determination of DA was conducted via cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results showed that the modified electrodes exhibited high electrocatalytic activity towards the oxidation of DA in 0.1 M phosphate buffer solution (pH 6.9). Linear dependency of electrocatalytic oxidation current on DA concentrations was observed from 0.5 μM to 8 μM and detection limit was estimated to be 0.1 μM (S/N = 3). The developed electrode could serve as a viable platform for further studies on in vivo detection of DA.