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 5wt% exhibited the highest activity. Compared with that of rGO, the nanocomposite presented superior high sensitivity with detection limit of 5nM, excellent selectivity, wide linear range (0.01-60μM) 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.