Graphene coated by polydopamine/multi-walled carbon nanotubes modified electrode for highly selective detection of dopamine and uric acid in the presence of ascorbic acid

Graphene (GR) was easily coated with a reactive biopolymer polydopamine (Pdop), and the Pdop functionalized graphene (Pdop@GR) novel nanomaterial was obtained by dispersing graphene in a dopamine solution and mildly stirring at room temperature. Meanwhile, a new modified electrode based on three-dimensional (3D) Pdop@GR-multiwalled carbon nanotubes (MWCNTs) hybrid nanomaterial has been prepared and applied on the simultaneous electrochemical determination of dopamine (DA) and uric acid (UA). The interference test showed that the coexisted ascorbic acid (AA) had no electrochemical interference toward DA and UA. Under the optimum conditions, the calibration curves for DA and UA were obtained in the range of 7.0-297.0 mu M and 20.0-320.0 mu M with detection limits (S/N = 3) of 1.0 x 10(-6) M and 1.5 x 10(-5) M, respectively. Importantly, the proposed method offers promise for rapid, simple, selective and cost-effective analysis of small biomolecules. (C) 2016 Elsevier B.V. All rights reserved.