L-Cysteine-coated CdSe/CdS core-shell quantum dots as selective fluorescence probe for copper(II) determination
L-Cysteine-coated CdSe/CdS core-shell quantum dots as selective fluorescence probe for copper(II) determination
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DOI：
10.1016/j.microc.2008.01.008
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发表时间：
2008-08-01
影响因子：
4.8
通讯作者：
Wang, Hong
中科院分区：
文献类型：
--
作者：
Zhang, Yao-hai;Zhang, Hua-shan;Wang, Hong
量子点（QD）或半导体纳米晶体在过去几年中受到极大的关注。本文制备了L-半胱氨酸包覆的CdSe/CdS核壳量子点（λ（cm）=585 nm），具有良好的水溶性。这些纳米晶体的光致发光的半峰全宽（FWHM）非常窄（约30 nm），并且量子产率（QY）相对于在乙醇中的罗丹明6 G（QY=95%）为15%。当溶液中存在过量的游离L-半胱氨酸时，L-半胱氨酸包覆的CdSe/CdS量子点的荧光强度显示出改善的稳定性。结果表明，L-半胱氨酸修饰的CdSe/CdS量子点的荧光仅能被Cu（Ⅱ）离子猝灭，对其它生理上重要的阳离子如Ca ~（2+）、Mg ~（2+）、Zn ~（2+）、Al ~（3+）、Fe ~（3+）、Mn ~（2+）和Ni ~（2+）等不敏感。线性范围为1.0 × 10 ~（-8）~ 2.0 × 10 ~（-7）mol L ~（-1），检出限为3.0 × 10 ~（-9）mol L ~（-1）（SIN=3）。方法用于蔬菜样品中Cu ~（2+）的测定，回收率为99.6- 105.8%。(C)2008年由Elsevier B. V.出版。
Quantum dots (QDs) or semiconductor nanocrystals have been receiving great interest in the last few years. In this paper, L-cysteine-coated CdSe/CdS core-shell QDs (lambda(cm)=585 nm) have been prepared, which have excellent water-solubility. The full width at half maximum (FWHM) of the photoluminescence of these nanocrystals is very narrow (about 30 nm), and the quantum yield (QY) is 15% relative to Rhodamine 6G in ethanol (QY=95%). With excess free L-cysteine in the solution, the fluorescence intensity of L-cysteine-coated CdSe/CdS QDs showed improved stability. It was found that the fluorescence of L-cysteine-capped CdSe/CdS QDs could be quenched only by copper (II) ions and was insensitive to other physiologically important cations, such as Ca2+, Mg2+, Zn2+, Al3+, Fe3+, Mn2+ and Ni2+, etc. Based on this finding, the quantitative analysis of Cu2+ with L-cysteine-capped CdSe/CdS QDs has been established. The linear range was from 1.0 x 10(-8) to 2.0 x 10(-7) mol L-1 and the limit of detection (LOD) was 3.0 x 10(-9) mol L-1 (SIN=3). The proposed method has first been applied to the determination of CU2+ in vegetable samples with recoveries of 99.6-105.8%. (C) 2008 Published by Elsevier B.V.