▎ 摘　　要

A simple and highly sensitive electrochemical sensor based on graphene oxide modified glassy carbon electrode (GO/GCE) is reported for the detection of hydrazine (HDZ), ascorbic acid (AA) and hydrogen peroxide (H2O2). GO nanosheets were synthesized by the oxidation of natural graphite powder via a modified Hummer's method. The structural and surface characteristics of GO were investigated by x-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, Ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) spectroscopy, Raman spectroscopy and thermogravimetric analysis (TGA). The electrochemical behaviour of the GO/GCE was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry. Under optimized GO concentration, GO/GCE showed stable and admirable electrocatalytic response towards the oxidation of HDZ and AA, and the reduction of H2O2 at low over potentials. GO/GCE showed promising detection ability for HDZ, AA, and H2O2 with high sensitivity, wider linear detection range and lower LOD. The obtained LOD values were 1.04, 0.5 and 4 mu M for HDZ, AA, and H2O2 respectively. Furthermore, GO/GCE exhibited good stability, reusability, reproducibility and anti-interference capability. The superior electrical conductivity, strong adsorptive ability and large surface area of GO nanosheets are responsible for the excellent electrocatalytic activity of the present GO-based sensor. This study reveals that GO is a promising candidate as the electrochemical sensor.