Single Gold Nanoparticle-Based Colorimetric Detection of Picomolar Mercury Ion with Dark-Field Microscopy

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• 作者：Xiaojun Liu ; Zhangjian Wu ; Qingquan Zhang ; Wenfeng Zhao ; Chenghua Zong ; Hongwei Gai
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：February 16, 2016
• 年：2016
• 卷：88
• 期：4
• 页码：2119-2124
• 全文大小：348K
• ISSN：1520-6882

文摘

Mercury severely damages the environment and human health, particularly when it accumulates in the food chain. Methods for the colorimetric detection of Hg²⁺ have increasingly been developed over the past decade because of the progress in nanotechnology. However, the limits of detection (LODs) of these methods are mostly either comparable to or higher than the allowable maximum level (10 nM) in drinking water set by the US Environmental Protection Agency. In this study, we report a single Au nanoparticle (AuNP)-based colorimetric assay for Hg²⁺ detection in solution. AuNPs modified with oligonucleotides were fixed on the slide. The fixed AuNPs bound to free AuNPs in the solution in the presence of Hg²⁺ because of oligonucleotide hybridization. This process was accompanied by a color change from green to yellow as observed under an optical microscope. The ratio of changed color spots corresponded with Hg²⁺ concentration. The LOD was determined as 1.4 pM, which may help guard against mercury accumulation. The proposed approach was applied to environmental samples with recoveries of 98.3 ± 7.7% and 110.0 ± 8.8% for Yuquan River and industrial wastewater, respectively.