1,2-dithioglycol functionalised carbon nitride quantum dots as a “turn – off” fluorescent sensor for mercury ion detection

ABSTRACT

A kind of 1,2-dithioglycol (DTG) functionalised carbon nitride quantum dots (DTG-CNQDs) was designed for the first time by modifying DTG on the surface of carbon nitride quantum dots (CNQDs). The as-prepared DTG-CNQDs exhibit strong blue fluorescence under ultraviolet light and have a high quantum yield of 27%. Experiments show that Hg²⁺ has a good quenching effect on the fluorescence of DTG-CNQDs. In phosphate buffer (PBS, 10 mM, pH 6.0), the fluorescence quenching rate (F₀/F) has a good linear relationship with the concentration of Hg²⁺ in the range of 0.020–0.50 μM with detection limit of 0.63 nM. This fluorescent probe possesses high sensitivity and good selectivity, which can be applied in the rapid detection of Hg²⁺ in tap and lake water samples.

KEYWORDS:

• DTG-CNQDs
• surface functionalisation
• fluorescent probe
• mercury ion

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 21375116]; a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and Jiangsu Province research program on analytical methods and techniques on the shared platform of large-scale instruments and equipment [grant number BZ 201409]. Results of TEM and XPS in the experiment were provided by Test Center of Yangzhou University.