▎ 摘　　要

In the present study, the magnetic graphene quantum dot (Fe3O4 MNPs-GQDs) was synthesized successfully and characterized by using fourier transform infrared spectroscopy, transmission electron microscopy and atomic force microscopy (AFM). For the first time, as-synthesized GQDs and Fe3O4 MNPs-GQDs was electrodeposited on GCE by cyclic voltammetry (CV) in the potential range from -1.0 to 1.0 V and the prepared films were used for detection of Vitamin C at physiological pH. Herein, we explore the electrocatalytical activity of Fe3O4 MNPs-GQDs. We have illustrated that the as-obtained Fe3O4 MNPs-GQDs exhibited a much higher electroactivity individual GQDs and Fe3O4 MNPs for the electrooxidation and detection of Vitamin C which was about two fold higher than for GQDs. More importantly, a substantial (+0.21 V) decrease in the overvoltage of the Vitamin C oxidation reaction (compared to ordinary electrodes) was observed using Mag-GQDs-GCE. In general, Fast response time, excellent catalytic activity, lower overvoltage and ease of preparation are the advantages of the proposed nanosensor.