设计合成了一种简单的酰腙类结构的增强型荧光探针HM, 实现了对锌离子(Zn2+)的高选择性识别。运用ESI-MS质谱、荧光光谱和紫外-可见光谱等手段研究了探针HM对Zn2+的识别过程。紫外光谱测试表明, 当向探针HM中加入Zn2+后, 386 nm处的吸收峰逐渐减弱, 在420 nm处出现了新的吸收峰, 并且强度逐渐增大, 直至达到平衡, 等吸收点为396 nm。荧光光谱分析表明, 探针HM能够高选择性地识别Zn2+。在发射波长510 nm处的荧光增强2.5倍, 最低检出限为1.0×10-5 mol/L、量子产率为0.02。该识别过程为PET(光诱导电子转移机理)和CHEF(螯合荧光增强机理)共同作用的结果。通过电喷雾质谱和Jobs plot 实验证明探针HM与Zn2+以1∶1配位, 平衡常数(K)达到4.05×106 L·mol-1。

A simple fluorescent probe HM based on acylhydrazone structure was synthesized for recognition of zinc ion (Zn2+). The recognition process of Zn2+ was studied by ESI-MS, fluorescence spectroscopy and UV-Vis spectroscopy. UV-Vis titration test shows that the addition of Zn2+ into HM aqueous solution caused gradually drop of the absorption peak at 386 nm. At the same time, a new absorption peak at 420 nm appeared and the intensity gradually increased until equilibrium. A sharp isosbestic point at 396 nm was obtained. Florescence spectroscopy indicates that the fluorescent probe HM exhibites high selectivity for detection of Zn2+. The fluorescence intensity was increased by 2.5 times at excited wavelength of 510 nm. The lowest detection limit of HM for Zn2+ is up to 1.0×10-5 mol/L and the fluorescence quantum yield is 0.02. The recognition process is presumed to be caused by PET (photoinduced electron transfer) process combining with CHEF (Chelation enhanced fluorescence) mechanism. The Jobs plot and ESI-MS results demonstrate a 1∶1 stoichiometric host-guest complex for probe molecular HM and Zn2+, with the association constant being calculated as K=4.05×106L·mol-1.