Ligand displacement-induced fluorescence switch of quantum dots for ultrasensitive detection of cadmium ions

详细信息    查看全文

• 作者：Xianyun Hu ; Kao Zhu ; Qingsheng Guo ; Yuqian Liu ; Mingfu Ye ; Qingjiang Sun
• 关键词：Quantum dot ; 1 ; 10-Phenanthroline ; Photoluminescence ; Sensor ; Ligand displacement ; Cadmium ions
• 刊名：Analytica Chimica Acta
• 出版年：17 February, 2014
• 年：2014
• 卷：812
• 期：Complete
• 页码：191-198
• 全文大小：2568 K

文摘

This paper reports the construction of a simple CdTe quantum dots (QDs)-based sensor with 1,10-phenanthroline (Phen) as ligand, and the demonstration of a novel ligand displacement-induced fluorescence switch strategy for sensitive and selective detection of Cd²⁺ in aqueous phase. The complexation of Phen at the surface quenches the green photoluminescence (PL) of QDs dominated by a photoinduced hole transfer (PHT) mechanism. In the presence of Cd²⁺, the Phen ligands are readily detached from the surface of CdTe QDs, forming [Cd(Phen)₂(H₂O)₂]²⁺ in solution, and as a consequence the PL of CdTe QDs switches on. The detection limit for Cd²⁺ is defined as 鈭?.01 nM, which is far below the maximum Cd²⁺ residue limit of drinking water allowed by the U.S. Environmental Protection Agency (EPA). Two consecutive linear ranges allow a wide determination of Cd²⁺ from 0.02 nM to 0.6 渭M. Importantly, this CdTe QDs-based sensor features to distinctly discriminate between Cd²⁺ and Zn²⁺, and succeeds in real water samples. This extremely simple strategy reported here represents an attempt for the development of fluorescent sensors for ultrasensitive chemo/biodetection.