Zinc Oxide Anchored Porous Reduced Graphene Oxide: Electrode Material for Sensing of Ezetimibe

Abstract

A new and sensitive electrochemical sensing platform was developed based on zinc oxide anchored porous reduced graphene oxide nanocomposite (ZnO/prGO) for a dyslipidemic agent, ezetimibe (EZT). ZnO nanoparticles (NPs) were prepared by treating zinc acetate solution with an environmental friendly precursor, Balanitesroxburghii date fruit extract (desert date). The nanocomposite, ZnO/prGO was prepared by hydrothermal treatment followed by ultrasonication method. ZnO/prGO was characterized systematically by X-ray diffraction, UV-visible spectroscopic, FT-infrared spectroscopic, scanning electron microscopic-EDX and electrochemical impedance spectroscopic techniques. The sensing platform was fabricated by drop casting ZnO/prGO suspension onto the surface of glassy carbon electrode (GCE) to obtain ZnO/prGO/GCE. The proposed sensor, ZnO/prGO/GCE, showed excellent sensitivity for EZT due to porogenic nature and improved electron /mass transfer capability of the electrode material. EZT exhibited an anodic peak with 18-fold enhancement in peak current at ZnO/prGO/GCE when compared to that at bare GCE. Linearity was observed between the peak current and concentration of EZT in the range of 0.1–51.1 μM and 0.05–62.5 μM for square wave voltammetric (SWV) and differential pulse voltammetric (DPV) methods, respectively. SWV method was developed for the first time for the determination of EZT with a lowest limit of detection of 0.03 μM. The fabricated electrochemical sensor displayed good selectivity for EZT in the presence of additives and excipients. The applicability of the proposed sensor was demonstrated by determining EZT in spiked urine samples and pharmaceutical formulations. The results of analysis were found to be accurate with more than 97% recovery and precise with RSD values of less than 3.0%.