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

In this work, a novel electrochemical sensor was introduced 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. Our 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 ranges from 5-180 µM, 180-1000 µM with a detection limit of 1.3 µM for DA and two linear responses ranges from 5-20 µM and 20-1000 µM with a detection limit of 1.4 µM for EP. Also, the electrochemical oxidation of DA and EP was well recovered in pharmaceutical formulations.