Electrochemical Sensor for Voltammetric Determination of Bilirubin Based on Nafion/Graphene Oxide Nanocomposite Film Glassy Carbon Electrode A sensitive electrochemical sensor for the determination of bilirubin (BR) at the Nafion-electrochemically reduced graphene oxide (Nafion/ER-GO) nanocomposite modified glassy carbon electrode (GCE) was presented. The electrochemical oxidation behaviors of bilirubin at the Nafion/ER-GO modified glassy carbon electrode were studied in acetone 0.05 M H2SO4 containing as the supporting electrolyte. Compared with bare GCE, the proposed integrated sensor showed improved analytical performance characteristics in catalytic oxidation of bilirubin. The electrochemistry of BR on Nafion/ER-GO modified glassy carbon electrodes were studied by cyclic voltammetry (CV) and square-wave voltammetry (SWV). In cyclic voltammetric responses, the oxidation peak current of BR obtained at the Nafion/ER-GO modified glassy carbon electrode was 2 times greater than that of bare glassy carbon electrode. At optimized conditions, the calibration curve for BR showed two linear segments: the first linear segment increased from 2.0 to 20 and second linear segment increased up to 70 µM. The detection limit was determined as 0.84 µM (0.049 mg dL-1) using SWV. Finally, the proposed method was successfully used to determine bilirubin in serum samples.
