▎ 摘　　要

In this work, a novel and robust electrochemical sensor was developed by modifying EDTA and beta-cyclodextrin functionalized reduced graphene oxide (EDTA-beta-CD-rGO) onto the Glassy carbon electrodes (GCE) to quantify 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH). The morphology and structures of the nanocomposite were characterized by the UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectra, Scanning electronic microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The nanocomposite exhibits great electrochemical signal enhancement towards DPPH oxidation, which attributes to the good electrical properties and high specific surface area of rGO along with the enrichment of amounts of DPPH onto the EDTA-beta-CD-rGO/GCE by forming host-guest inclusion complex and chelated compounds with beta-CD and EDTA, respectively. Under the optimal conditions, the linear range for DPPH was from 1.0 x-10(-8) to 0.01 mol/L with a low detection limit of 3.0 x-10(-9) mol/L. The sensor also showed the advantages of simple preparation, low cost, good stability and repeatability. These characteristics make the sensor promising for the detection of DPPH. Moreover, EDTA-beta-CD-rGO showed strong DPPH scavenging activity, and it can be used as an artificially synthesized antioxidant. [GRAPHICS]