Self-assembled oligo(phenylene ethynylene)s/graphene nanocomposite with improved electrochemical performances for dopamine determination

In this work, a novel 1,4-bis (4- aminophenylethynyl)benzene (OPE-NH₂, a symmetric linear conjugated oligo(phenylene ethynylene)s derive) and chemically-reduced graphene oxide (rGO) nanocomposite (OPE-NH₂/rGO) was synthesized by a simple self-assembly method. The OPE-NH₂/rGO nanocomposite was stable and water soluble. The formation of OPE-NH₂/rGO nanocomposite was ascribed to the π–π stacking interaction between the conjugated structure of OPE-NH₂ and rGO as well as the electrostatic force between the amino group of OPE-NH₂ and the carboxyl group on rGO, which was characterized by FT-IR, UV–vis spectra and fluorescence spectra. The OPE-NH₂/rGO nanocomposite exhibited significantly improved electrocatalytic activity to the oxidization of dopamine (DA) than that of rGO or OPE-NH₂. The electrochemical performances of OPE-NH₂/rGO were dependent on the OPE-NH₂ contents, and OPE-NH₂ content of 5 wt% exhibited the highest activity. Compared with that of rGO, the nanocomposite presented superior high sensitivity with detection limit of 5 nM, excellent selectivity, wide linear range (0.01–60 μM) and good stability on the determination of DA. The practical application of the developed OPE-NH₂/rGO nanocomposite modified electrode was successfully demonstrated for DA determination in human serum samples.