Mercury (II) Detection Using Nitrogen and Sulfur co-doped Carbon Quantum Dots and Fluorescence Quenching Assay

Mercury (II) Detection Using Nitrogen and Sulfur co-doped Carbon Quantum Dots and Fluorescence Quenching Assay

Mercury is a highly toxic and potentially bioaccumulative heavy metal ion that can cause severe health problems in humans even at very low concentrations. Thus, the development of a simple, rapid, and sensitive assay for the effective detection of mercury ions at trace levels is of great importance. Here, nitrogen and sulfur co-doped carbon quantum dots (N,S-CQD) were synthesized by hydrothermal treatment of chitosan in the presence of thiourea and citric acid with a quantum yield (QY) up to 33.0 % and used as a selective fluorescent probe to detect mercury ions (Hg2+). The synthesized N,S-CQD showed ultrasensitive ability to detect Hg2+ ions in the presence of 11 interfering metal ions, with a low detection limit (~4 nM) over a wide linear range from ~5- 160 nM. The sensing performance of N,S-CQD probe in real sample applications was evaluated by the detection of Hg2+ in lake water samples.