{'fraction_non_alphanumeric': 0.05242718446601942, 'fraction_numerical': 0.030097087378640777, 'mean_word_length': 5.286585365853658, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Phosphorescence Analysis of Cd~(2+) with ZnS∶Mn~(2+) 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 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.