Simultaneous electroanalytical sensing of dopamine and epinephrine using TiO2/reduced graphene oxide nanocomposite modified glassy carbon electrode

This work introduces a novel electrochemical sensor for simultaneous determination of dopamine (DA) and epinephrine (EP) by modifying a glassy carbon electrode (GCE) with reduced graphene oxide (RGO) and titanium dioxide (TiO2) nanoparticles. The RGO/TiO2 nanocomposite characterization was investigated by using field emission scanning electron microscopy (FE-SEM), elemental mapping, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-Ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods were used for electrochemical measurements. This study showed that the resultant RGO/ TiO2 modified GCE is highly sensitive and selective for the simultaneous determination of DA and EP, and provided two linear responses rangeing from 5-180 and 180-1000 μM with a detection limit of 1.3 μM for DA and two linear responses ranging from 5-20 and 20-1000 μM with a detection limit of 1.4 μM for EP. In addition, the electrochemical oxidation of DA and EP was well recovered in pharmaceutical formulations.