双色量子点多层膜用于水环境中微量汞离子的定量检测

Detection of mercury ions in water environment based on bi-color quantum dot multilayer films

目的建立水环境中微量汞离子的定量检测方法。方法 通过层层自组装法将表面带有负电荷的Cd Te量子点与聚电解质PDDA交替沉积在石英板上,成功制备出双色量子点多层膜。在该方法中Hg2+对Cd Te量子点有荧光猝灭作用,据此发展了一种直接检测Hg2+的新型双色Cd Te量子点多层膜传感器。结果 实验结果表明:当Hg2+浓度在1.0×10-9~1.0×10-5mol/L范围时,量子点多层膜的荧光强度与Hg2+浓度之间有良好的线性关系,检出限为2.5×10-10mol/L。结论 与传统Hg2+检测方法相比,双色Cd Te荧光量子点多层膜作为一种新型传感器,具有快速、简单、选择性高和灵敏度高等优点,有望应用于水环境中痕量Hg2+的定量检测与早期预警。

Objective To establish a method for determination of mercury ions in water environment. Methods The functional multilayer films were assembled by layer-by-layer (LbL) deposition of oppositely charged CdTe quantum dot (QDs) and poly (dimethyldiallylemmonium chloride) (PDDA). The bi-color quan-tum dot multilayer films were used as fluoresce probes for the quantitative determination of trace amounts of Hg2+ based on the evident quenching action of Hg2+ on the fluorescence of CdTe QDs.Results Experimental results showed that the quenching in fluorescence intensity of multilayer films was linearly proportional to the concentration of Hg2+ in the range of 1.0×10?9to 1.0×10?5 mol/L and the detection limit was 2.5×10-10 mol/L. Conclusion Compared with the traditional Hg2+ detection method, this method has the advantages of simpli-fication, rapidness, high selectivity and high sensitivity. Furthermore, the proposed method was applied to the determination of trace Hg2+ in water samples with satisfactory results.