Electrochemical Sensor Based on Three-Dimensional rGO/ZnO composite for dopamine detection

Abstract

In this study, a novel dopamine (DA) electrochemical sensor was designed based on three-dimensional reduced graphene oxide (3D rGO) and zinc oxide (ZnO). The morphologies and structures of 3D rGO and 3D rGO-ZnO were characterized via scanning electron microscopy, infrared spectrophotometry, and X-ray diffraction. Electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry were used to investigate the electrochemical behavior of DA on the 3D rGO-ZnO/glassy carbon electrode (GCE). The results showed that the 3D rGO-ZnO/GCE improved electron transferability. In a phosphate-buffered solution with pH 7.0, the 3D rGO-ZnO/GCE exhibited an excellent catalytic activity for DA oxidation. In the ranges of 0.01-70 pM and 70-500 µM, the peak current exhibited an excellent linear relationship with DA concentration and the detection limit was 0.06 nM. The proposed sensor has high sensitivity, low-detection limit, and a wide linear range and can be used as an alternative analytical tool to detect DA in real samples.