N-doped carbon dots for highly sensitive and selective sensing of copper ion and sulfide anion in lake water. Issue 2 (April 2021)

• Record Type: Journal Article
• Authors: Ge, Jia; Shen, Yanmei; Wang, Weixia; Li, Yuqing; Yang, Yu
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 2(2021)
• Publication Date: 2021-04
• Subjects: Nitrogen-doped -- Carbon dots -- Copper ion -- Sulfide anion -- Fluorescence sensor; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105081
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Water contamination by copper ions (Cu 2+ ) and sulfide anions (S 2- ) has been a longstanding human health hazard. The limitations of current detection strategies have created a high demand for effectively monitoring the concentrations of these ions in water systems. A facile fluorescent bioassay for Cu 2+ and S 2- was developed in this study based on "on-off-on" fluorescent nitrogen-doped carbon dots (N-CDs). N-CDs were synthesized for the first time via thermal treatment using hexamethylene-tetramine and ammonium citrate precursors. The obtained CDs were highly stable in aqueous solution, with a strong green emission and a 51.2% quantum yield. The maximum fluorescence emission peak was observed at 478 nm for a 360-nm excitation. Notably, the fluorescence intensity of N-CDs can be quenched by a factor of 6 by Cu 2+, which can be applied to Cu 2+ assays ranging from 0.05 to 5 μM with a limit of detection (LOD) of 25 nM. Interestingly, further addition of S 2- recovered the fluorescence of the N-CD@Cu 2+ nanocomplex, which can be used to quantify S 2- in a broad range from 0.05 to 10 μM with an LOD of 32 nM. The N-CD and N-CD@Cu 2+ nanocomplexes were also demonstrated to be highly specific towards Cu 2+ and S 2-, respectively. Finally, the sensor was successfully applied to lake water for detecting both Cu 2+ and S 2-, demonstrating excellent application prospects for analytical chemistry and environmental remediation. Graphical Abstract: ga1 Highlights: A fluorescent "on-off-on" biosensor is developed for the sensing of Cu 2+ and S 2- based on N-CDs. The amino groups on the surface of the N-CDs have a high binding affinity towards Cu 2+ . This proposed method is applicable for the detection of Cu 2+ and S 2- in real samples.