Colorimetric Signal Amplification Assay for Mercury Ions Based on the Catalysis of Gold Amalgam

详细信息    查看全文

• 作者：Zhengbo Chen ; Chenmeng Zhang ; Qinggang Gao ; Guo Wang ; Lulu Tan ; Qing Liao
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：November 3, 2015
• 年：2015
• 卷：87
• 期：21
• 页码：10963-10968
• 全文大小：451K
• ISSN：1520-6882

文摘

Mercury is a major threat to the environment and to human health. It is highly desirable to develop a user-friendly kit for on-site mercury detection. Such a method must be able to detect mercury below the threshold levels (10 nM) for drinking water defined by the U.S. Environmental Protection Agency. Herein, we for the first time reported catalytically active gold amalgam-based reaction between 4-nitrophenol and NaBH₄ with colorimetric sensing function. We take advantage of the correlation between the catalytic properties and the surface area of gold amalgam, which is proportional to the amount of the gold nanoparticle (AuNP)-bound Hg²⁺. As the concentration of Hg²⁺ increases until the saturation of Hg onto the AuNPs, the catalytic performance of the gold amalgam is much stronger due to the formation of gold amalgam and the increase of the nanoparticle surface area, leading to the decrease of the reduction time of 4-nitrophenol for the color change. This sensing system exhibits excellent selectivity and ultrahigh sensitivity up to the 1.45 nM detection limit. The practical use of this system for Hg²⁺ determination in tap water samples is also demonstrated successfully.