2-巯基苯并咪唑保护的铜纳米团簇的制备及银离子检测

以2-巯基苯并咪唑为保护剂,聚乙烯吡咯烷酮为稳定剂,水合肼为还原剂,“一锅法”合成2-巯基苯并咪唑保护的,高稳定性、强荧光、大斯托克斯位移的铜纳米团簇(Cu NCs),并用于检测水样中的银离子含量。采用透射电子显微镜(TEM)和X射线光电子能谱(XPS)对铜纳米团簇的结构进行表征,通过荧光光谱和紫外可见光谱对其光学性能进行研究。研究表明:该铜纳米团簇的最大激发和发射波长分别为340和558 nm,在日光灯和紫外灯下分别为无色和橙色。Cu NCs具有较高的分散性,尺寸大小为2~3 nm。在最佳反应条件下,铜纳米团簇可以选择性地被银离子猝灭,且灵敏度高,线性范围为1~40μmol/L,检测限为0.5μmol/L。该方法用于检测实际水样(自来水、湖水)中银离子的浓度,结果令人满意,表明在环境监测中有非常高的应用价值。

Synthesis of 2-Mercaptobenzimidazole-Functionalized Water-Soluble Copper Nanoclusters and Their Application to the Determination of Ag+

We reported a direct one-pot approach, employing 2-mercaptobenzimidazole as a protective agent, polyvinyl pyrrolidone as a stabilizer and hydrazine hydrate as a reducing agent, for rapid preparation of highly stable, strong fluorescent, large Stokes shift fluorescent copper nanoclusters (Cu NCs) from Cu(NO₃)₂ in aqueous solution at room temperature. Meanwhile, we studied the possibility of the Cu NCs to detect silver ion in water samples. The structure of Cu NCs was characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The optical performance was studied using fluorescence spectroscopy and UV-visible absorption spectroscopy. The as-prepared Cu NCs exhibit a fluorescence emission at 559 nm, and show colorless and orange fluorescence under sunlight and UV light irradiation, respectively. The Cu NCs were highly dispersed with the size of 2~3 nm. In addition, it exhibits good water solubility, excellent photostability and high stability toward high concentration of sodium chloride. Under optimal reaction conditions, the Cu NCs can be used for the highly sensitive and selective detection of silver ions (Ag⁺) in aqueous solution. The fluorescence intensity quenches linearly within the range of 1 to 40 μmol/L with high sensitivity (LOD=0.5 μmol/L, S/N=3) and this sensing system has been successfully applied for environmental water sample analysis.