Carbon Nitride Quantum Dots: A Novel Chemiluminescence System for Selective Detection of Free Chlorine in Water
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- 作者：Yurong Tang ; Yingying Su ; Na Yang ; Lichun Zhang ; Yi Lv
- 刊名：Analytical Chemistry
- 出版年：2014
- 出版时间：May 6, 2014
- 年：2014
- 卷：86
- 期：9
- 页码：4528-4535
- 全文大小：457K
- 年卷期：v.86,no.9(May 6, 2014)
- ISSN：1520-6882
文摘
A facile one-step microwave-assisted approach for the preparation of strong fluorescent carbon nitride quantum dots (g-CNQDs) by using guanidine hydrochloride and EDTA as the precursors was developed. Strong chemiluminescence (CL) emission was observed when NaClO was injected into the prepared g-CNQDs, and a novel CL system for direct detection of free chlorine was established. Free residual chlorine in water was sensitively detected with a detection limit of 0.01 渭M and had a very wide detection range of 0.02 to 10 渭M. On the basis of CL spectral, UV鈥搗isible absorption spectral, and electron spin resonance (ESR) spectral studies, as well as investigations on the effects of various free radical scavengers, a possible CL mechanism was proposed. It was suggested that the radiative recombination of oxidant-injected holes and electrons in the g-CNQDs accounted for the CL emission. Meanwhile, 1O2 on the surface of g-CNQDs, generated from some reactive oxygen species in the g-CNQDs-NaClO system, could transfer energy to g-CNQDs and thus further enhance the CL emission. The CL system is highly sensitive and differentiable, opening a new field for the development of novel CL-emitting species, but also expanding the conventional optical utilizations of g-CNQDs.