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

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 Agenc...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2015-11, Vol.87 (21), p.10963-10968
Main Authors: Chen, Zhengbo, Zhang, Chenmeng, Gao, Qinggang, Wang, Guo, Tan, Lulu, Liao, Qing
Format: Article
Language:English
Subjects:
Amalgams
Analytical chemistry
Bioassays
Catalysis
Catalysts
Colorimetry
Colorimetry - methods
Dental Amalgam
Detection
Gold
Gold - chemistry
Mercury
Mercury (metal)
Mercury - analysis
Nanoparticles
Nanostructure
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Summary: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.
ISSN:0003-2700
1520-6882
DOI:10.1021/acs.analchem.5b02812