A simple and efficient voltammetric sensor for dopamine determination based on ZnO nanorods/electro-reduced graphene oxide composite

Abstract

A nanocomposite of ZnO nanorods and electro-reduced graphene oxide (ZnONRs/ERGO) was prepared as cost-effective and efficient electrocatalyst for voltammetric detection of dopamine via a facile hydrothermal treatment followed by an electrochemical reduction. The ZnONRs were uniformly supported on the surface of conductive ERGO nanosheets, which enlarged the electroactive surface area and lowered the electron transfer resistant significantly. As a result, ZnONRs/ERGO modified glass carbon electrode (ZnONRs/ERGO/GCE) showed much more remarkable electrocatalytic activity toward dopamine oxidation than the controlled electrodes, with amplified response current and decreased over-potential. The extraordinary electrocatalytic activity is mainly attributed to the synergistic catalytic effects from ZnONRs and ERGO nanosheets. Using second derivative linear voltammetry (SDLSV), two wide dynamic response ranges (0.01 to 6.0 μM and 6.0 to 80 μM) were achieved at the ZnONRs/ERGO/GCE with an extremely low limit of detection (LOD) of 3.6 nM. The ZnONRs/ERGO/GCE also demonstrates excellent anti-interference ability and good repeatability, reproducibility as well as stability. Moreover, the ZnONRs/ERGO/GCE realized the accurate detection of dopamine concentration in human serum with good recoveries. Considering the outstanding advantages including low cost, simple manufacture, high efficiency, and superior sensing properties, ZnONRs/ERGO shows tremendous application prospects on real detection of catecholamine neurotransmitters.