锰掺杂硫化锌量子点室温磷光检测镉离子

Phosphorescence Analysis of Cd^(2+) with ZnS∶Mn^(2+) Quantum Dots at Room-Temperature

作为一类理想的磷光探针,量子点近年来在环境污染物定性定量分析方面应用广泛。量子点是半径小于或接近于激子玻尔半径的一类半导体纳米晶。以巯基丙酸(MPA)为表面修饰剂制备了稳定的水溶性掺杂型Zn S∶Mn2+量子点并应用于金属Cd2+的检测。在p H 7.0的PBS缓冲介质中,Cd2+可使Zn S∶Mn2+体系磷光猝灭,强度变化与Cd2+浓度呈良好线性关系,其线性范围为8×10-8~8×10-6mol/L,方法检测下限为3.86×10-8mol/L;利用荧光光谱、紫外可见吸收光谱研究了Zn S:Mn2+纳米晶结构及其光谱特性,探讨了识别Cd2+的可能机理。该方法应用于汾河水中Cd2+的检测,回收率为93.2%~97.1%。

Quantum dots（QDs） as a type of ideal phosphorescence probes have been extensively studied in qualitative and quantitative analysis of environmental pollutants. QDs are a type of semiconductor nanocrystals with radius smaller than or close to Bohr-exciton radius. In this paper, the stable water soluble QDs were prepared with mercaptopropionic acid（MPA）as a surface modifier, the prepared Zn S∶Mn2＋nanocrystal was used to detect Cd2 ＋. In p H 7.0 PBS, Cd2 ＋could quench the phosphorescence intensity of the Zn S∶Mn2＋system significantly. The linear relationship between Cd2＋and phosphorescence intensity was found, and the linear range was 8×10-8~8×10-6mol/L with detection limit of 3.86×10-8mol/L. Then its nano-crystalline structure and the spectral properties were analyzed by fluorescence and UV-Vis spectroscopy, and the possible mechanism of Cd2＋was discussed. The recoveries of 93.2%~97.1% Cd2＋in the water sample from Fenhe were found.