ZnO interrelated graphene matrix-based sensors for quercetin

Abstract

An electrochemical study of quercetin (QUR) was carried out voltammetrically using graphene (Gr) and zinc oxide nanoparticles (ZnO) modified carbon paste electrodes (CPE). The effect of phosphate buffer solution (0.2 M PBS) of various pH was tested and we found that pH 6.0 was optimum. The electrochemical analysis of QUR involves a redox-coupled reaction with one oxidation peak at 0.356 V and a reduction peak at 0.324 V with a peak strength of 1.05 μA and 0.413 μA, respectively. The peak current obtained at the modified electrode was higher than the bare CPE, indicating the electrocatalytic behavior of the modifier. Surface characterization of Gr-ZnO/CPE was evaluated using X-ray diffraction (XRD) studies, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Energy dispersive X-ray spectroscope (EDS). Sweep rate investigation provided knowledge about reaction mechanisms involving transferring an equal number of electrons and protons. The electrochemical process was governed by adsorption. The limit of detection (LOD) was computed to be 18.0 nM. The developed electrode material was utilized to determine QUR in real samples, which exhibited excellent recovery, demonstrating the utility of the proposed electrode.