Institute of Applied Chemistry, Department of Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
Analyst. 2013 Apr 7;138(7):2181-91. doi: 10.1039/c3an36742h. Epub 2013 Feb 21.
Since zinc ions play an important role in various physiological activities, developing a facile detection method for Zn(2+) is highly desirable. Owing to their superior optical properties, semiconductor quantum dots (QDs) have been developed as a promising alternative for organic fluorophores in fluorescence analysis. In this study, water soluble di-2-picolylamine-dithiolcarbamate (DPA-DTC)/proline-dithiolcarbamate (P-DTC) co-capped CdSe/ZnS QDs as a sensitive and selective "turn-on" fluorescence probe for Zn(2+) was reported. The probe was easily obtained via ligand exchange. The initial bright fluorescence of QDs was effectively quenched by DPA-DTC that acted as an effective hole trapper. Upon complexation with Zn(2+), the formation of Zn(2+)-DPA-DTC complex altered the energetic position of the HOMO for DPA-DTC, which rendered it unfavorable for the hole transfer. Thus the QDs PL was switched on. Under optimal conditions, a good linear relationship between the fluorescence response and Zn(2+) concentration could be obtained in the range from 0.9 to 16 μM. The limit of detection for Zn(2+) was found to be 0.7 μM. Furthermore, the present probe exhibited a high selectivity for Zn(2+) over other common metal ions and was successfully used in the detection of Zn(2+) in simulated biological fluids.
由于锌离子在各种生理活动中起着重要作用，因此开发一种简便的 Zn(2+)检测方法是非常可取的。由于其优越的光学性质，半导体量子点 (QDs) 已被开发为荧光分析中有机荧光团的一种很有前途的替代品。在这项研究中，报道了水溶性二-2-吡啶基胺-二硫代氨基甲酸酯 (DPA-DTC)/脯氨酸-二硫代氨基甲酸酯 (P-DTC) 共帽 CdSe/ZnS QDs 作为一种灵敏和选择性的“开启”荧光探针用于 Zn(2+)。该探针可通过配体交换轻松获得。DPA-DTC 作为有效的空穴捕获剂，有效地猝灭了初始明亮的 QDs 荧光。与 Zn(2+)络合后，Zn(2+)-DPA-DTC 配合物的形成改变了 DPA-DTC 的 HOMO 能态，使其不利于空穴转移。因此，QDs 的 PL 被开启。在最佳条件下，荧光响应与 Zn(2+)浓度之间可以在 0.9 到 16 μM 的范围内获得良好的线性关系。Zn(2+)的检测限被发现为 0.7 μM。此外，该探针对 Zn(2+)具有很高的选择性，优于其他常见的金属离子，并成功用于模拟生物液中 Zn(2+)的检测。
