Phosphorescence Analysis of Cd2+ with ZnS∶Mn2+ Quantum Dots at Room-Temperature
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 ZnS∶Mn2+ nanocrystal was used to detect Cd2+.In pH 7.0 PBS,Cd2+ could quench the phosphorescence intensity of the ZnS∶Mn2+ system significantly.The linear relationship between Cd2+ and phosphorescence intensity was found,and the linear range was 8×10-8～8×10-6 mol/L with detection limit of 3.86×10-s mol/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.
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