Analytical Sciences

Reversible Fluorescence Probe Based on N-Doped Carbon Dots for the Determination of Mercury Ion and Glutathione in Waters and Living Cells

Xiaohan SUN, Shenghong YANG, Mingzhen GUO, Shuang MA, Mingda ZHENG, and Jiang HE

State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China

An “on-off-on” mode was developed for the detection of mercury ion (Hg²⁺) and glutathione (GSH) with high sensitivity and selectivity based on the nitrogen-doped carbon dots (N-CDs) fluorescent probe. The N-CDs were synthesized through microwave treatment of citric acid and diethylenetriamine for 2 min, and exhibited excellent fluorescence properties and high quantum yield (27.7%). The fluorescence intensity of the N-CDs could be significantly quenched by Hg²⁺ (turn-off). Upon addition of GSH, the fluorescence intensity of the N-CDs-Hg²⁺ system could be recovered clearly (turn-on). The limit of detection of Hg²⁺ and GSH was 23 and 59 nM, respectively. Moreover, the “on-off-on” probe was successfully applied to the determination of Hg²⁺ in tap water and water from the Yellow River. Meanwhile, due to bright luminescence, good biocompatibility and low cytotoxicity, the N-CDs-based probe was successfully employed as visualizing the intracellular Hg²⁺ and GSH sensors in live HeLa cell.

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