碳量子点荧光传感法测定牛奶中的三聚氰胺

A fluorescence sensor for the determination of melamine in milk using carbon quantum dots as fluorescent probe

基于碳量子点溶液荧光被汞离子猝灭后加入三聚氰胺又能恢复荧光的特性建立了一种测定三聚氰胺的简易方法。研究了碳量子点、碳量子点-Hg^(2+)和碳量子点-Hg^(2+)-三聚氰胺体系的Zeta电位,提出了该测试体系荧光猝灭与恢复是由碳量子点表面电荷改变引起的机理。研究了碳量子点浓度、猝灭剂汞离子用量、溶液pH、反应时间等因素对测定体系荧光猝灭与恢复的影响,确定了最佳测定条件。在最佳测定条件下,三聚氰胺在0.05~4.0μg/mL浓度范围内与体系荧光恢复程度呈线性关系,其线性方程为:y=1.135+0.9673c,线性相关系数R^2=0.9966,检出限为0.01μg/mL,能满足实际样品中三聚氰胺检测的要求。

A simple method for determination of melamine was developed based on fluorescence quencher and recovery of carbon quantum dots （CQDs） using mercury cation as fluorescence quencher and melamine as fluorescence recovery agent. Zeta-potential of the particles which were in carbon quantum dots systems, carbon quantum dots-mercury cations system and carbon quantum dots-mercury cations-melamine system was determined. We believe that the surface charge change of carbon quantum dots may be the mechanism of fluorescence quenched and recovered may based on the Zeta- potential of the particles in this system. The influential factors including concentration of carbon quantum dots, amount of mercury cations added, pH of the solution, reaction time were investigated and the optimum condition were determined. Under the optimum conditions, the response was linearly proportional to the concentration of melamine within the range of 0. 05 - 4.0 mg/mL, the limit of detection was 0.01 mg/mL. The linear equation was y = 1. 135 ＋ 0. 9673c, the linear coefficient was 0. 9966.