Nitrogen-doped carbon quantum dots: Facile synthesis and application as a “turn-off” fluorescent probe for detection of Hg2+ ions

• Published in: Biosensors & bioelectronics Vol. 55; pp. 83 - 90
• Main Authors: Zhang, Ruizhong, Chen, Wei
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.05.2014; Elsevier
• Subjects: Biological and medical sciences; biosensors; Biotechnology; Carbon; Carbon - chemistry; detection limit; Fluorescence; fluorescent dyes; Fluorescent Dyes - analysis; Fluorescent Dyes - chemical synthesis; Folic acid; Fundamental and applied biological sciences. Psychology; Ions - analysis; Ions - chemistry; lakes; Mercury; Mercury - analysis; Mercury - chemistry; metal ions; Molecular Probe Techniques; monitoring; nitrogen; Nitrogen - chemistry; Quantum Dots; Sensor; Spectrometry, Fluorescence - methods; tap water; Water Pollutants, Chemical - analysis; Fluorescence; Quantum dots; Carbon; Mercury; Folic acid; Sensor; Quantum dot; Nanoparticle; Nitrogen; Probe; Detector; Detection; Application
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2013.11.074

A facile, economical and straightforward hydrothermal strategy is used to prepare highly luminescent nitrogen-doped carbon quantum dots (N-CQDs) by using folic acid as both carbon and nitrogen sources. The as-prepared N-CQDs have an average size of 4.5±1.0nm and exhibit excitation wavelength-dependent fluorescence with the maximum emission and excitation at 390 and 470nm, respectively. Furthermore, due to the effective quenching effect of Hg2+ ions, such N-CQDs are found to serve as an effective fluorescent sensing platform for lable-free sensitive detection of Hg2+ ions with a detection limit of 0.23μM. The selectivity experiments reveal that the fluorescent sensor is specific for Hg2+ even with interference by high concentrations of other metal ions. Most importantly, the N-CQDs-based Hg2+ ions sensor can be successfully applied to the determination of Hg2+ in tap water and real lake water samples. With excellent sensitivity and selectivity, such stable and cheap carbon materials are potentially suitable for monitoring of Hg2+ in environmental application. [Display omitted] •N-doped carbon quantum dots (N-CQDs) are synthesized by using folic acid as carbon and nitrogen sources.•The N-CQDs with average size of 4.5±1.0nm exhibit excitation wavelength-dependent fluorescence.•The N-CQDs can serve as an effective fluorescent sensing platform for lable-free sensitive detection of Hg2+ ions.•The N-CQDs-based Hg2+ ions sensor can be applied to real lake water samples with excellent sensitivity and selectivity.