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

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 μM 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.