Amperometric Detection of Dopamine based on a Graphene Oxide/PEDOT:PSS Composite Electrode

Dopamine (DA) is a hormone and a neurotransmitter that plays many important roles within the brain and body. It is an organic compound in the catecholamines and phenethylamines groups. A considerable effort has been made since its discovery, and numerous techniques for DA detection have been developed. Graphene and its derivatives have great potential for the development of sensors and biosensors. Since it has excellent characteristics, such as good conductivity and a large surface area, a graphene-based biosensor is expected to have high sensitivity, selectivity, and long-term stability characteristics. Graphene oxide (GO) was synthesized using a chemical method through graphite oxidation. Graphene oxide/poly (3,4-ethylene-dioxythiophene):poly (4-styrenesulfonate) (GO/PEDOT:PSS) composite films were prepared using an electropolymerization method on the surface of the working electrode. The properties of this composite electrode were characterized by cyclic voltammetry (CV) and scanning electron microscopy (SEM). The performance of the composite film was evaluated using three-electrode systems that consisted of a glassy carbon electrode (GCE) modifying a composite film electrode as a working electrode, a platinum electrode as an auxiliary electrode, and Ag/AgCl as a reference electrode. The variation of the composite electrode was applied and evaluated to DA electrochemical sensing. The GO/PEDOT:PSS-modified electrode also exhibits high performance with a low detection limit of 1 µM. The results obtained have shown that GO/PEDOT:PSS/GCE composites are promising candidates for modifying electrode material used in electrochemical sensing.