Dual-mode colorimetric/fluorometric sensor for the detection of glutathione based on the peroxidase-like activity of carbon quantum dots

In the current investigation, fluorescent carbon quantum dot nanoparticles were prepared using hydrothermal method. In order to achieve green preparation, waste corncob was used as raw material. Transmission electron microscope was used to examine the urface morphology of the synthesized fluorescent carbon quantum dot nanoparticles. Optical characterization was done by analyzing the ultraviolet–visible spectroscopy and fluorescence absorption spectrum. The peroxidase activity and catalytic performance of corncob fluorescent carbon quantum dots have been researched and compared with some simulated enzymes, and corncob fluorescent carbon quantum dots with peroxisase-like activity and fluorescence characteristics were used for the detection of glutathione by dual-mode colorimetric/fluorometric sensor. Our experimental results displayed that the corncob fluorescent carbon quantum dots have nanostructures and the catalytic activity of corncob fluorescent carbon quantum dots was better than that of other nanoparticles. The detection results of glutathione show that the limit of detection was 8.0133 nmol/L for the fluorometric sensor and the limit of detection was 0.3024 μmol/L for the colorimetric sensor with good selectivity and high sensitivity, exhibiting their potential for application in nanosensors.