Dual-Emission Fluorescent Silica Nanoparticle-Based Probe for Ultrasensitive Detection of Cu2+

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• 作者：Chenghua Zong ; Kelong Ai ; Guo Zhang ; Hongwei Li ; Lehui Lu
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：April 15, 2011
• 年：2011
• 卷：83
• 期：8
• 页码：3126-3132
• 全文大小：891K
• 年卷期：v.83,no.8(April 15, 2011)
• ISSN：1520-6882

文摘

An effective dual-emission fluorescent silica nanoparticle-based probe has been constructed for rapid and ultrasensitive detection of Cu²⁺. In this nanoprobe, a dye-doped silica core served as a reference signal, thus providing a built-in correction for environmental effects. A response dye was covalently grafted on the surface of the silica nanoparticles through a chelating reagent for Cu²⁺. The fluorescence of the response dye could be selectively quenched in the presence of Cu²⁺, accompanied by a visual orange-to-green color switch of the nanoprobe. The nanoprobe provided an effective platform for reliable detection of Cu²⁺ with a detection limit as low as 10 nM, which is nearly 2 脳 10³ times lower than the maximum level (20 渭M) of Cu²⁺ in drinking water permitted by the U.S. Environmental Protection Agency (EPA). The high sensitivity was attributed to the strong chelation of Cu²⁺ with polyethyleneimine (PEI) and a signal amplification effect. The nanoprobe constructed by this method was very stable, enabling the rapid detection of Cu²⁺ in real water samples. Good linear correlations were obtained over the concentration range from 1 脳 10^鈭? to 8 脳 10^鈭? (R² = 0.99) with recoveries of 103.8鈭?9.14% and 95.5鈭?5.14% for industrial wastewater and lake water, respectively. Additionally, the long-wavelength emission of the response dye can avoid the interference of the autofluorescence of the biosystems, which facilitated their applications in monitoring Cu²⁺ in cells. Furthermore, the nanoprobe showed a good reversibility; the fluorescence can be switched 鈥渙ff鈥?and 鈥渙n鈥?by an addition of Cu²⁺ and EDTA, respectively.