Ultrasensitive Pb^sup 2+^ Detection by Glutathione-Capped Quantum Dots

Water-soluble and stable quantum dots (QDs), CdTe and CdZnSe, are applied for ultrasensitive ... detection. These QDs are capped with glutathione (GSH) shells. GSH and its polymeric form, phytochelatin, are employed by nature to detoxify heavy metal ions. As a result of specific interaction, the flu...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2007-12, Vol.79 (24), p.9452
Main Authors: Ali, Emril Mohamed, Zheng, Yuangang, Yu, Hsiao-hua, Ying, Jackie Y
Format: Article
Language:English
Subjects:
Analytical chemistry
Fluorescence
Ions
Quantum dots
Spectrum analysis
Studies
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Summary:Water-soluble and stable quantum dots (QDs), CdTe and CdZnSe, are applied for ultrasensitive ... detection. These QDs are capped with glutathione (GSH) shells. GSH and its polymeric form, phytochelatin, are employed by nature to detoxify heavy metal ions. As a result of specific interaction, the fluorescence intensity of GSH-capped QDs is selectively reduced in the presence of heavy metal ions such as ... The detection limit of ... is found to be 20 nM due to the superior fluorescence properties of QDs. Detailed studies by spectroscopy, microscopy, and dynamic light scattering show that competitive GSH binding of ... with the QD core changed both the surface and photophysical properties of the QDs. Fluorescence of QDs is quenched, and QD aggregation occurs. Coupling the GSH-capped QDs with a high-throughput detection system, we have developed a simple scheme for quick and ultrasensitive ... detection without the need for additional electronic devices. In the presence of ionic mixtures, our system is still capable of ... detection with a detection limit as low as 40 nM. The system only becomes less sensitive when the ionic mixture is present at a very high concentration (i.e., ≥50 ...M). (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0003-2700
1520-6882