An electrochemical sensor based on graphene/poly(brilliant cresyl blue) nanocomposite for determination of epinephrine

A graphene modified with poly(brilliant cresyl blue) (PBCB) glassy carbon electrode was fabricated by a simple method of drop-casting and two-step-electropolymerization for facilitating electrocatalytic detection of epinephrine (EP). Surface characterization of PBCB/graphene/GCE was conducted by electrochemical impedance spectroscopy (EIS), whose results showed that the electron transfer process at PBCB/graphene is faster than at bare GCE, graphene/GCE and PBCB/GCE. And the scanning electron microscopy (SEM) image confirmed the graphene dispersion incorporated with PBCB on the GCE. A noticeable enhancement in the microscopic area of the electrode resulted in an appreciable increase of the peak current of EP oxidation (similar to 9.4 times). The catalytic oxidation peak currents obtained from cyclic voltammetry (CV) increased linearly with EP concentrations in the range of 1.0 x 10(-6) to 1.0 x 10(-3) mol/L with the limit of detection 2.4 x 10(-7) mol/L (S/N = 3). Furthermore, the fabricated PBCB/graphene/GCE nanocomposite can determine EP in the presence of a large excess of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry (DPV). The modified electrode can be used for the determination of EP in practical pharmaceutical formulation. (C) 2016 Elsevier B.V. All rights reserved.