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Highly fluorescent carbon dots as nanoprobes for sensitive and selective determination of 4-nitrophenol in surface waters

We report on the synthesis of carbon dots (C-dots) by thermal carbonization of a mixture of ethyleneglycol bis-(2-aminoethyl ether)-N,N,N’,N’-tetraacetic acid (EGTA) and tris(hydroxymethyl)aminomethane (Tris). The resulting C-dots were characterized by X-ray diffraction, proton and carbon nuclear ma...

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Bibliographic Details
Published in:Mikrochimica acta (1966) 2015-01, Vol.182 (1-2), p.51-59
Main Authors: Ahmed, Gaber Hashem Gaber, Laíño, Rosana Badía, Calzón, Josefa Angela García, García, Marta Elena Díaz
Format: Article
Language:English
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Summary:We report on the synthesis of carbon dots (C-dots) by thermal carbonization of a mixture of ethyleneglycol bis-(2-aminoethyl ether)-N,N,N’,N’-tetraacetic acid (EGTA) and tris(hydroxymethyl)aminomethane (Tris). The resulting C-dots were characterized by X-ray diffraction, proton and carbon nuclear magnetic resonance, FTIR and fluorescence spectroscopy, and high-resolution TEM. The data reveal that the C-dots are mainly capped with hydroxy and carbonyl groups and are highly fluorescent with an emission peak that shifts from 427 to 438 nm if the excitation wavelength is increased from 310 to 360–370 nm. Fluorescence is quenched by 4-nitrophenol (4-NP), and this effect was exploited to design a simple and rapid protocol for the determination of 4-NP. The detection limit is 28 nM and the linear range extends from 0.1 to 50 μM. The method was successfully applied to the determination of 4-NP in spiked river and sea waters. Graphical abstract Contact quenching produced through the formation of a Meisenheimer complex with negative charge delocalized over the cyclohexadienine ring and the nitro group and positive charge distributed over an iminium group.
ISSN:0026-3672
1436-5073
DOI:10.1007/s00604-014-1302-x