新型荧光探针制备及茶叶中汞离子检测的研究

以S-亚硝基谷胱甘肽（GSNO）作为保护剂和还原剂合成了水溶性金纳米团簇AuNCs，建立了分析实际茶叶样品中汞离子（Hg2+）高灵敏的方法。通过透射电镜（TEM）、动态光散射仪（DLS）、紫外-可见吸收光谱（UV-VIS）和荧光光谱对所制备的S-亚硝基谷胱甘肽包被的金纳米团簇GSNO@AuNCs进行了表征，随着汞离子浓度的增加，体系的荧光被高效猝灭，以此构建了检测汞离子的荧光探针。探讨了pH值、盐离子浓度、反应时间和温度对其荧光性能的影响。在优化实验条件下，汞离子浓度在0.1～40.0 μmol/L范围内与GSNO@AuNCs的荧光强度呈良好的线性关系，线性回归方程为Y=1.392+27.28X，相关系数R2=0.999 5，检出限为0.033 μmol/L。同时初步构建了GSNO@AuNCs荧光探针应用于茶叶样品中汞离子的检测，结果满意。

Preparation of a novel fluorescence probe and its application in the detection of Hg2+ in tea

The water-soluble gold nanoclusters AuNCs was prepared based using S-nitrosoglutathione (GSNO) as protective agent and reducing agent, and the method for detecting the content of Hg2+ in tea samples was established. The gold nanoclusters coated with GSNO GSNO@AuNCs were characterized by transmission electron microscope (TEM), dynamic light scatterometer (DLS), ultraviolet-visible spectrophotometer (UV-VIS) and fluorescence spectroscopy. As the concentration of Hg2+ increased, the fluorescence intensity of the GSNO@AuNCs was efficiently quenched. Based on this principle, the fluorescent probe for detecting the content of Hg2+ was developed. The effects of pH, NaCl concentration, reaction time and temperature on the fluorescence were examined. Under the optimal test conditions, the fluorescence intensity of GSNO@AuNCs was linearly correlated with the concentration of Hg2+ in the range of 0.1-40.0 μmol/L, the linear regression equation was Y=1.392+27.28X, with coefficient (R2) 0.999 5, and the detection limit was 0.033 μmol/L. Furthermore, the GSNO@AuNCs fluorescent probe was applied to the determination of Hg2+ in the tea samples, and the results was satisfactory.