文献类型：期刊文献

英文题名：An improved method for ratiometric fluorescence detection of pH and Cd2+ using fluorescein isothiocyanate-quantum dots conjugates

作者：Gui, Rijun[1,2];An, Xueqin[1];Huang, Wenxue[1]

机构：[1]E China Univ Sci & Technol, Sch Chem & Mol Engn, Dept Phys Chem, Shanghai 200237, Peoples R China;[2]Shanghai Jiao Tong Univ, Sch Chem & Chem Engn, Dept Chem, Shanghai 200240, Peoples R China

年份：2013

卷号：767

期号：1

起止页码：134

外文期刊名：ANALYTICA CHIMICA ACTA

收录：;EI(收录号：20131216138475);WOS:【SCI-EXPANDED(收录号:WOS:000316440000017)】；

基金：This work was financially supported by the National Natural Science Foundation of China (21273073, 21076124 and 51173104), the National High-Tech Research and Development Plan of China (2011AA06A107), the Fundamental Research Funds for the Central Universities of China (WK0913002), the Nanotechnology program of Science and Technology Committee of Shanghai (11nm0503500) and the Nature Science Keystone Foundation of Shanghai (08jc1408100).

语种：英文

外文关键词：Quantum dots; Fluorescein isothiocyanate; Ratiometric sensor; Fluorescence

摘要：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.