A rapid and label-free dual detection of Hg (II) and cysteine with the use of fluorescence switching of graphene quantum dots

Li, Zhuo, Wang, Yong, Ni, Yongnian, & Kokot, Serge (2015) A rapid and label-free dual detection of Hg (II) and cysteine with the use of fluorescence switching of graphene quantum dots. Sensors and Actuators B: Chemical: international journal devoted to research and development of physical and chemical transducers, 207(Part A), pp. 490-497.

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A simple and rapid method of analysis for mercury ions (Hg2+) and cysteine (Cys) was developed with the use of graphene quantum dots (GQDs) as a fluorescent probe. In the presence of GQDs, Hg2+ cations are absorbed on their negatively charged surface by means of electrostatic interactions. Thus, the fluorescence (FL) of the GQDs would be significantly quenched as a result of the FL charge transfer, e.g. 92% quenching at 450 nm occurs for a 5 μmol L−1 Hg2+ solution. However, when Cys was added, a significant FL enhancement was observed (510% at 450 nm for a 8.0 μmol L−1 Cys solution), and Hg2+ combined with Cys rather than with the GQDs in an aqueous solution. This occurred because a strong metalsingle bondthiol bond formed, displacing the weak electrostatic interactions, and this resulted in an FL enhancement of the GQDs. The limits of detection (LOD) for Hg2+ and Cys were 0.439 nmol L−1 and 4.5 nmol L−1, respectively. Also, this method was used successfully to analyze Hg2+ and Cys in spiked water samples.

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28 citations in Web of Science®
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ID Code: 88567
Item Type: Journal Article
Refereed: Yes
Keywords: Graphene quantum dots; Citric acid; Mercury (II) ions; Cysteine; Fluorescence switching
DOI: 10.1016/j.snb.2014.10.071
ISSN: 0925-4005
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2014 Elsevier B.V.
Deposited On: 09 Nov 2015 22:45
Last Modified: 09 Nov 2015 22:45

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