期刊
ANALYTICA CHIMICA ACTA
卷 767, 期 -, 页码 134-140出版社
ELSEVIER
DOI: 10.1016/j.aca.2013.01.006
关键词
Quantum dots; Fluorescein isothiocyanate; Ratiometric sensor; Fluorescence
资金
- National Natural Science Foundation of China [21273073, 21076124, 51173104]
- National High-Tech Research and Development Plan of China [2011AA06A107]
- Fundamental Research Funds for the Central Universities of China [WK0913002]
- Nanotechnology program of Science and Technology Committee of Shanghai [11nm0503500]
- Nature Science Keystone Foundation of Shanghai [08jc1408100]
In this study, thioglycolic acid capped-CdTe quantum dots (QDs) were modified by polyethylenimine (PEI), and then combined with fluorescein isothiocyanate (FITC) to fabricate FITC-CdTe conjugates. The self-assembly of FITC, CdTe and PEI was ascribed to electrostatic interactions in aqueous solution. The resulting conjugates were developed toward two routes. In route one, ratiometric photoluminescence (PL) intensity of conjugates (I-FITC/I-QDs) was almost linear toward pH from 5.3 to 8.7, and a ratiometric PL sensor of pH was favorable obtained. In route two, firstly added S2- induced remarkable quenching of QDs PL peak (at the OFF state), which was restored due to following addition of Cd2+ (at the ON state). In the conjugates, successive introduction of S2- and Cd2+ hardly influenced on FITC PL peaks. According to this PL OFF-ON mode, a ratiometric PL method for the detection of Cd2+ was achieved. Experimental results confirmed that the I-FITC/I-QDs exhibited near linear proportion toward Cd2+ concentration in the range from 0.1 to 15 mu M, and the limit of detection was 12 nM. Interferential experiments adequately testified that the proposed sensors of pH and Cd2+ were practicable in real samples and complex systems. In comparison with conventional analytical techniques, the ratiometric PL method was simple, rapid, economic and highly selective. (C) 2013 Elsevier B.V. All rights reserved.
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