▎ 摘　　要

In this work, new detection route for ascorbic acid was designed. First, highly luminescent sulfur and nitrogen doped graphene quantum dots (S, N-GQDs) were prepared via simple hydrothermal method using citric acid and thiourea as the C, N and S sources respectively. The prepared S, N-GQDs are characterized by XRD, HRTEM, FTIR, EDS and PL. Investigations showed that prepared S, N-GQDs have a good photostability and excitation-dependent emission fluorescence. Prepared S, N-GQDs showed maximum excitation wavelength and emission wavelength at 400 and 462 nm, respectively. In the following, prepared S, N-GQDs were applied as a photoluminescence probe for detection of ascorbic acid (AA). The designed sensor was based on "off-on" detection mode. The developed sensor had a linear response to AA over a concentration range of 10-500 mu M with a detection limit of 1.2 mu M. The regression equation is Y= 0.0014 X + 1.2036, where Y and X denote the fluorescence peak intensity and AA concentration, respectively.