State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing 210093, China.
Anal Chim Acta. 2011 Dec 5;708(1-2):134-40. doi: 10.1016/j.aca.2011.09.044. Epub 2011 Oct 8.
In this paper, cobalt (Co(2+))-doped (CoD) ZnS quantum dots (QDs) are synthesised in aqueous solution and characterised for the first time. L-Cysteine (L-Cys) ligands on the surface of CoD ZnS QDs can bind 2,4,6-trinitrotoluene (TNT) to form Meisenheimer complexes (MHCs) mainly through acid-base pairing interactions between TNT and L-Cys and the assistance of hydrogen bonding and electrostatic co-interactions among L-Cys intermolecules. The aggregation of inter-dots induced by MHCs greatly influenced the light scattering property of the QDs in aqueous solution, and Rayleigh scattering (RS) enhancement at the defect-related emission wavelengths as well as its left side was observed with the excitation of CoD ZnS QDs by violet light. RS enhancement, combining with the quenching of the orange transition emission induced by TNT anions, resulted in a change in the ratiometric visualisation of the system being investigated. A novel CoD ZnS QD-based hybrid ratiometric chemosensor has therefore been developed for simple and sensitive analysis of TNT in water. This ratiometric probe can assay down to 25 nM TNT in solution without interference from a matrix of real water sample and other nitroaromatic compounds. Because of the excellent electron-accepting ability and strong affinity of TNT to L-Cys on the surface of CoD ZnS QDs, the CoD photoluminescent nanomaterials reported here are well suited for detecting ultra-trace TNT and for distinguishing different nitro-compounds in aqueous solution.
本文首次合成了在水溶液中钴（Co(2+))掺杂的（CoD）ZnS 量子点（QDs）并对其进行了表征。表面的 L-半胱氨酸（L-Cys）配体可以与 2,4,6-三硝基甲苯（TNT）结合形成 Meisenheimer 配合物（MHCs），主要通过 TNT 和 L-Cys 之间的酸碱配对相互作用以及 L-Cys 分子间氢键和静电相互作用的辅助。MHCs 引起的量子点间聚集极大地影响了水溶液中量子点的光散射性质，并且在 CoD ZnS QDs 被紫光激发时观察到在与缺陷相关的发射波长处的瑞利散射（RS）增强以及其左侧。RS 增强与 TNT 阴离子诱导的橙色跃迁发射的猝灭相结合，导致所研究系统的比率可视化发生变化。因此，开发了一种基于 CoD ZnS QD 的新型比率型混合化学传感器，用于在水中简单灵敏地分析 TNT。该比率探针可在溶液中检测低至 25 nM 的 TNT，而不受实际水样和其他硝基芳烃化合物基体的干扰。由于 TNT 对 CoD ZnS QDs 表面 L-Cys 的优异电子接受能力和强亲和力，所报道的 CoD 光致发光纳米材料非常适合检测超痕量 TNT 并区分水溶液中的不同硝基化合物。
