CdS-Eu(Ⅲ)体系荧光恢复的磷酸根离子可视化测定

Fluorescence Recovery and Visual Detections for Phosphate Based on CdS-Eu(Ⅲ) System

以聚丙烯酸(PAA)为稳定剂,成功合成了水溶性的CdS量子点(QDs).CdS QDs表面的羧基能与Eu3+结合导致QDs聚集,有效引发QDs间能量的转移,致使CdS QDs荧光显著猝灭.当加入PO3-4时,由于PO3-4与Eu3+的结合能力强于CdS QDs表面的羧基,CdS QDs荧光强度又逐渐恢复.由此建立一种基于CdSEu(Ⅲ)体系荧光恢复可视化测定磷酸根离子的新方法.该方法灵敏、简单,检测限为0.078μmol·L-1.

In this study, the water-soluble CdS quantum dots （QDs） stabilized by polyacrylic acid （PAA） were success- fully synthesized. Eu3＋ ions could efficiently induce clustering of QDs through the carboxylic acid groups on surface of CdS QDs, which resulted in apparent fluorescence quenching due to energy transfer between CdS QDs. Because the chelation ability between Eu3＋ and PO43- was stronger than that between Eu3＋ and carboxyl groups, the fluorescence intensity of CdS QD gradually recovered when PO44- were introduced to the CdS-Eu（ Ⅲ） system. Thus a novel fluorescence recovery and visual method for the determination of PO4 3- has been developed based on CdS-Eu（Ⅲ ） system. The present novel assay with a detection limit （3a） of 0. 078μmol· L-1 is very simple and sensitive.