Nitrogen-doped carbon dots used as an “on–off–on” fluorescent sensor for Fe3+ and glutathione detection
© 2020 Elsevier Ltd A novel kind of nitrogen-doped carbon dots (N-CDs) with strong blue fluorescence emission was synthesized via microwave pyrolysis method using humic acid, urea, and citric acid as the precursor. We found that the fluorescence emission of N-CDs can be firstly quenched by Fe3+ (turn-off) and then recovered by glutathione (turn-on). Moreover, N-CDs applied as an “on-off-on” fluorescent sensor for the detection of Fe3+ and glutathione (GSH) was further studied in this work. N-CDs showed good selectivity and sensitivity towards Fe3+ than other metal ions, and the limit of detection (LoD) is lower to 0.102 μM. Furthermore, the stable N-CDs/Fe3+exhibited a high sensitivity detection for GSH with a LoD of 0.226 μM. In addition, density functional theory calculations were further performed to reveal the mechanism of the “turn-off” and “turn-on” process. According to geometries and frontier molecular orbital (FMO) results, N-CDs exhibited strong interaction with Fe3+ rather than other metal ions, and the N-CDs/Fe3+ complex exhibited the highest stability among other complexes. Furthermore, this “on–off–on” fluorescent sensor was successfully applied as a stain-screening detector for Streptococcus thermophilus with high production of GSH.
Publication Source (Journal or Book title)
Dyes and Pigments
Liang, Y., Xu, L., Tang, K., Guan, Y., Wang, T., Wang, H., & Yu, W. (2020). Nitrogen-doped carbon dots used as an “on–off–on” fluorescent sensor for Fe3+ and glutathione detection. Dyes and Pigments https://doi.org/10.1016/j.dyepig.2020.108358