Glassy carbon electrode modified by ZnO/GO composite for electrochemical detection of diclofenac

Abstract

In 2019, diclofenac (DCF) was classified as a substance of high priority for monitoring in order to protect aquatic environments [1]. Electroanalytical methods have numerous advantages compared to conventional instrumental methods when it comes to detection and monitoring of DCF in water, however, there is still a need for developing electrodes with sufficiently good analytical properties. Herein, a composite of zinc oxide (ZnO) and graphene oxide (GO) (0.005 wt % relative to ZnO) was characterized by XRD, Raman spectroscopy, and FESEM imaging, and used to prepare an ink that was applied to a glassy carbon electrode (GCE). After in situ reduction of GO, the obtained ZnO_0.005rGO@GCE electrode was tested for the detection and quantification of DCF in 0.1 M phosphate buffer (pH=7) by cyclic voltammetry (CV) (Fig. 1A) and differential pulse voltammetry (DPV) (Fig. 1B). It was found that the ZnO_0.005rGO@GCE electrode is active for detection of DCF by both CV and DPV method. Significant improvement in sensitivity, as well as lower limit of detection/quantification was achieved by DPV method.