聚乙烯吡咯烷酮保护荧光铜纳米团簇制备及其对乙醇的快速准确检测

乙醇含量的精确定量检测对于环境监测、临床诊断、食品检测以及饮用酒水都至关重要。以氯化铜（CuCl₂）为铜源、聚乙烯吡咯烷酮（PVP）为保护剂、2-巯基苯并噻唑（MBT）为稳定剂、抗坏血酸（AA）为还原剂，利用声化学还原法，以绿色简单、快速便捷的手段成功合成出具有橙色荧光的铜纳米团簇（PVP-Cu NCs）。利用紫外可见吸收光谱、荧光光谱、红外光谱、透射电镜和X射线光电子能谱技术研究其结构和性能，发现PVP-Cu NCs的最佳激发波长和发射波长分别为340和580 nm，其平均粒径为6.0 nm。PVP-Cu NCs可通过聚集诱导猝灭机制实现对乙醇的灵敏检测，其荧光强度与乙醇含量在体积分数5%~45%范围内呈现出良好的线性关系，且PVP-Cu NCs可制作成乙醇检测试纸，对乙醇进行可视化检测。

Preparation of Polyvinylpyrrolidone-Protected Fluorescent Copper Nanoclusters for Rapid and Accurate Detection of Ethanol

Accurate quantitative detection of ethanol (EtOH) content is essential for environmental monitoring, clinical diagnosis, food testing, and drinking alcohol. A simple and green fluorescence colorimetry method utilizing sonochemical reduction method for the rapid and efficient detection of EtOH in alcoholic beverages has been established. The fluorescent copper nanoclusters (PVP-Cu NCs) were synthesized by using CuCl₂ as a copper source, 2-mercaptobenzothiazole (MBT) as a stabilizing agent, polyvinylpyrrolidone (PVP) as a protecting agent and ascorbic acid (AA) as a reducing agent. The resultant PVP-Cu NCs had a spherical shape with an average diameter of 6.0 nm and a strong fluorescent orange emission characteristic peak at 580 nm upon 340 nm excitation. The fluorescence copper nanoclusters possessed the advantages of excellent time, ultraviolet radiation and salt resistance stability. We found that PVP-Cu NCs had a good responsiveness to EtOH, and the fluorescence intensity was inversely proportionate to the EtOH volume fractions between 5% and 45% as a consequence of inducing aggregation of PVP-Cu NCs via changing its double layer and affecting its stability in the studied system. Based on the established calibration, the EtOH content was effectively evaluated with good precision. Furthermore, visible color transformation of this sensor paper was observed in the EtOH content range of 20%-60%, implying utility for visual EtOH detection. It is worth mentioning that the assay was successfully applied for the quantification of EtOH in commercial drink samples and the satisfying results were obtained.