谷胱甘肽包覆的水溶性碲化镉量子点在铅、汞离子检测中的荧光特性

Fluorescence Characteristic of Glutathione-capped Water-soluble CdTe Quantum Dots in Detection of Lead and Mercury Ions

利用谷胱甘肽（简称GSH）包覆的水溶性碲化镉量子点在与铅（Ⅱ）或汞（Ⅱ）离子混合后会发生荧光猝灭现象,其荧光强度的衰减程度与离子浓度成正比。根据这一原理,采用荧光分光光度法,利用量子点的荧光猝灭性质进行铅（Ⅱ）和汞（Ⅱ）的检测。当谷胱甘肽稳定的碲化镉量子点浓度为0.5μmol.L-1,溶液中铅（Ⅱ）浓度为10 nmol.L-1时,其相对荧光强度衰减幅度为22%;在同等碲化镉量子点浓度条件下,溶液中汞（Ⅱ）浓度为25 nmol.L-1时,其相对荧光强度衰减幅度为20%。铅（Ⅱ）和汞（Ⅱ）的线性范围分别为0.01-0.05,0.025-0.25μmol.L-1,检出限（3S/N）分别为0.01,0.025μmol.L-1。

Fluorescence quenching effect of glutathione（GSH）-capped,water soluble CdTe quantum dots（QD′s） was observed when mixed with solution containing Pb（Ⅱ） or Hg（Ⅱ） ion,and the magnitude of decrease in fluorescence intensity was found to keep direct proportionality with the concentration of Pb（Ⅱ） or Hg（Ⅱ） ion present.Based on this fact,a fluorospectrophotometric method for detection of Pb（Ⅱ） or Hg（Ⅱ） ion utilizing the fluorescence quenching effect of GSH capped CdTe QD′s was proposed.By taking concentration of GSH-capped CdTe QD′s at 0.5 μmol·L-1,the magnitude of decrease in fluorescence intensity of 22%（relative %） was obtained in solution containing 10 nmol·L-1 Pb（Ⅱ） ion,and of 20%（relative %） was obtained in solution containing 25 nmol·L-1 of Hg（Ⅱ） ion.Linearity ranges of Pb（Ⅱ） and Hg（Ⅱ） found were 0.01-0.05 μmol·L-1 and 0.025-0.25 μmol·L-1,with detection limits of 0.01 and 0.025 μmol·L-1 respectively.