Ultrasensitive and selective detection of Cu²⁺ in aqueous solution with fluorescence enhanced CdSe quantum dots

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• 作者：Ke Zhang ; Junkang Guo ; Jingjing Nie ; Binyang Du ; Duanjun Xu
• 关键词：CdSe quantum dots ; Cu2+ detection ; Fluorescence response
• 刊名：Sensors and Actuators B: Chemical
• 出版年：January, 2014
• 年：2014
• 卷：190
• 期：Complete
• 页码：279-287
• 全文大小：2951 K

文摘

Trace Cu²⁺ ions in aqueous solution were detected with ultra-sensitivity and excellent selectivity by using CdSe quantum dots (QDs) with enhanced fluorescence properties as fluorescent reporters. CdSe QDs were first synthesized by using aqueous route with 3-mercaptopropionic acid (3-MPA) as capping agent. By further thermal-annealing the as-prepared 3-MPA capped CdSe QDs in the presence of imidazole (IM) under nitrogen atmosphere at 70 掳C, the fluorescence quantum yields of CdSe QDs in aqueous solution could be dramatically enhanced to be 鈭?0.9%. These CdSe QDs with enhanced fluorescence exhibited fast fluorescence response (within 1 min), ultra-sensitivity and excellent selectivity toward Cu²⁺ ions over other metal ions in aqueous solution. The Cu²⁺-induced aggregation of CdSe QDs led to the significant fluorescence quenching of the CdSe QDs. The limit of detection (LOD) calculated for Cu²⁺ could reach as low as 0.13-0.16 ppb (2.0-2.5 nM). The co-existence of other metal ions did not interfere with the sensing of trace Cu²⁺ ions in aqueous solution.