Fluorescence turn-off detection of hydrogen peroxide and glucose directly using carbon nanodots as probes

In this paper, carbon nanodots (C-dots) were prepared using a hydrothermal method and were characterized by UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy and atomic force microscopy. The as-prepared C-dots show a blue emission at 410 nm and the diameter of the C-dots was in the range from 4 nm to 10 nm. The fluorescence of the as-prepared C-dots is linearly quenched by H2O2 in the presence of Fe2+. Hence, the C-dots can be directly used for the fluorescence detection of H2O2. The production of H2O2 from the oxidization of glucose by glucose oxidase results in the fluorescence quenching of C-dots in the presence of Fe2+, which can be used to detect glucose. In this paper, we first directly used C-dots as a fluorescence probe for the turn-off detection of H2O2 and glucose in the presence of Fe2+. After the experimental conditions were optimized, it was found that the fluorescence of the C-dots was quenched linearly by H2O2 over the concentration range 0.025–50 μM. What is more, a linear correlation was established between ΔF and the concentration of glucose in the range from 0.05 to 100 μM.