Facile synthesis of Au-graphene nanocomposite for the selective determination of dopamine

•A facile method for the fabrication of reduced graphene oxide/Au nanocomposite was demonstrated.•The reduced graphene oxide/Au nanocomposite was used to prepare modified electrode for electrochemical sensing.•Synergic effect of the nanocomposite for enhanced catalytic activity and conductivity was demonstrated.•The modified electrode showed good performance for the selective determination of dopamine in the presence of high concentration of ascorbic acid.

We report a facile strategy of graphene/gold nanocomposite based electrochemical biosensor that exhibit good sensitivity and high reproducibility. The graphene/gold nanocomposites were prepared by using sodium hydroxide acting as an accelerator for the reduction of gold ions. The graphene oxide was reduced by chemical and thermal methods after deposition of gold nanoparticles. The composition of the resulting materials was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and thermogravimetric analysis (TGA). Also, transmission electron microscope (TEM) was employed to demonstrate the successful deposition of gold nanoparticles on the surface of graphene sheets. The electrochemical behavior of dopamine (DA) on the surface of the graphene/gold nanocomposite modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In comparison to the reduced graphene oxide (rGO) modified electrode, the graphene/gold nanocomposite modified electrode shows good performance for the selective determination of DA. The nanocomposite modified electrode showed a low detection limit (0.095 μM), an enhanced electrochemical oxidation current for DA, and a good separation of potential of DA and ascorbic acid (AA).

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