Ultrasensitive Pb2+ detection based on fluorescence resonance energy transfer (FRET) between quantum dots and gold nanoparticles

• Published in: Analyst (London) Vol. 134; no. 7; pp. 1348 - 1354
• Main Authors: Wang, Xin, Guo, Xiangqun
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2009
• Subjects: Absorption; Analytical chemistry; Cadmium Compounds - chemistry; Chemistry; Cysteamine - chemistry; Exact sciences and technology; Fatty Acids - chemistry; Fluorescence Resonance Energy Transfer; Gold - chemistry; Hydrogen-Ion Concentration; Lead - analysis; Lead - chemistry; Metal Nanoparticles - chemistry; Microscopy, Electron, Transmission; Quantum Dots; Spectrometric and optical methods; Static Electricity; Sulfhydryl Compounds - chemistry; Tellurium - chemistry; Trace analysis; Water; Gold; Sensitivity; Chemical analysis; Efficiency; Nanoparticle; Detection limit; Ultratrace compound; Energy transfer; Fluorescence spectrometry
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/b822744f

Positively charged CdTe-QDs capped with cysteamine (CA-CdTe-QDs) and negatively charged AuNPs capped with 11-mercaptoundecanoic acid (MUA-AuNPs) have been prepared. They are water-soluble and biocompatible. An assay for the determination of Pb2+ has been proposed based on the modulation in FRET efficiency between QDs and AuNPs in the presence of Pb2+, which inhibits the interaction of the QD-AuNP assembly. This method is easy to operate and with remarkably high sensitivity. Under the optimum conditions, the response is linearly proportional to the concentration of Pb2+ in the range 0.22-4.51 ppm, and the detection limit is found to be 30 ppb of Pb2+ due to the superior fluorescence properties of QDs. The mechanism of this strategy is also discussed.