In this work, coumarin derivatives
(C) are used to enhance the
fluorescence of graphene quantum dots (GQDs) by covalently linking
the carboxyl groups on the edge of the GQD sheet. The as-synthesized
coumarin-modified graphene quantum dots (C-GQDs) have a uniform particle
size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs
have strong fluorescence emission, excellent photostability, and high
fluorescence quantum yield. C-GQDs and CN– can form
a C-GQDs+CN– system due to deprotonation and/or
intermolecular interactions. The introduced hydroquinone (HQ) is oxidized
to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN– system could lead to fluorescence enhancement of C-GQDs.
Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can
be used for quantitative detection of AA with CN– and HQ being used as substrates. Based on the above mechanism, C-GQDs
are developed as a multicomponent detection and sensing platform,
and the detection limits for CN–, HQ, and AA were
4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory
results were obtained when the platform was used to detect CN–, HQ, and AA in living cells and fresh fruits.
Air-permeable and flexible multifunctional textiles are highly desired for wearable electronics and portable device applications. However, fabricating textiles with novel multifunctionalities while maintaining their inherent porous and flexible characteristics still...
Owing to the hazardness, the sensitive and selective detection of cyanide (CN−) in water or water-containing systems has still been a puzzle plaguing scientists all around the world. In this paper, a novel fluorescence probe based on covalently functionalized graphene oxide (GO) by aminocoumarin for highly selective detection of CN− in deionized water was prepared under the action of EDC/NHS. This probe bears aminocoumarin group as the recognition site and fluorophore, and its fluorescence quantum yield is increased by 0.07. Simultaneously, by loading on GO, the dispersibility, selectivity and reversibility were soundly improved, which facilitated the detection process. The fluorescence spectra showed that the probe has high selectivity and sensitivity for cyanide, and has potential application in real water.
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