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

• The highly intrinsic peroxidase-like catalytic activity of N-GQDs is revealed.
• The activity of N-GQDs depended on pH, temperature and H2O2 concentration.
• The activity of N-GQDs has been used to the detection of H2O2 and glucose.
• This assay was suitable for the detection of glucose concentrations in real samples.

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 μM for H2O2 and 25 to 375 μM for glucose with a detection limit of 5.3 μM for H2O2 and 16 μM for glucose. This assay was also successfully applied to the detection of glucose concentrations in diluted serum and fruit juice samples.

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