Dual-modal Colorimetric and Fluorometric Method for Glucose Detection Using MnO2 Sheets and Carbon Quantum Dots

A novel dual-modal fluorometric and colorimetric method was developed for glucose detection using MnO2 sheets and carbon quantum dots(CQDs). The glucose could be oxidized by glucose oxidase, in accompanied with the formation of H2O2 intermediate, which resulted in the decomposition of MnO2 sheets, as well as the MnO2 sheets(brown) changed to Mn2+ ions(colorless), which induced the absorption of MnO2 sheet decreased and the fluorescence of CQDs increased, consequently. The linear detection ranges of glucose are 5–1000 µmol/L by fluorescent method and 5–60 µmol/L by colorimetric method. The limits of detection of these two measurements are 2.11 and 2.18 µmol/L, respectively. This method is easy to conduct, has reasonable sensitive and selectivity, and could be applied for the glucose detection in real human serum.