Recyclable Colorimetric Detection of Trivalent Cations in Aqueous Media Using Zwitterionic Gold Nanoparticles

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• 作者：Wenshu Zheng ; Huan Li ; Wenwen Chen ; Jian Ji ; Xingyu Jiang
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：April 5, 2016
• 年：2016
• 卷：88
• 期：7
• 页码：4140-4146
• 全文大小：416K
• ISSN：1520-6882

文摘

This report describes a colorimetric assay for trivalent metal cations (M³⁺) using gold nanoparticles (AuNPs)-modified with oppositely charged thiols that can form intermolecular zwitterionic surfaces. Zwitterionic AuNPs (Zw-AuNPs) are stable in high-salt solutions and well-dispersed in a wide range of pH values. M³⁺ including Fe³⁺, Al³⁺, and Cr³⁺ can effectively trigger the aggregation of Zw-AuNPs by interfering with their surface potential, and aggregated AuNPs can be regenerated and recycled by removing M³⁺. In our approach, the output signal can be observed by the naked eye within a micromolar (μM) concentration range. Uniquely, our assay is capable of discriminating Fe³⁺ from Fe²⁺, which is challenging using traditional approaches. More importantly, Zw-AuNPs can be stored stably at room temperature for a long period (3 months) with constant detection performance. Both the cost-effectiveness and the long shelf life make Zw-AuNPs ideal for detecting M³⁺ in resource-poor and remote areas.