Intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots and their application in the colorimetric detection of H2O2 and glucose

In this paper, the highly intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots (N-GQDs) is revealed. This activity was greatly dependent on pH, temperature and H2O2 concentration. The experimental results showed that the stable N-GQDs could be used for the detection of H2O2 and glucose over a wide range of pH and temperature, offering a simple, highly selective and sensitive approach for their colorimetric sensing. The linearity between the analyte concentration and absorption ranged from 20 to 1170 mu M for H2O2 and 25 to 375 mu M for glucose with a detection limit of 5.3 mu M for H2O2 and 16 mu M for glucose. This assay was also successfully applied to the detection of glucose concentrations in diluted serum and fruit juice samples. (C) 2015 Elsevier B.V. All rights reserved.