title: Colorimetric Signal Amplification Assay for Mercury Ions Based on the Catalysis of Gold Amalgam.
abstract: 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 Hg(2+). As the concentration of Hg(2+) 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 Hg(2+) determination in tap water samples is also demonstrated successfully.
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.
authors.forename: Chenmeng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.
authors.forename: Guo
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.|College of Resources Environment and Tourism, Capital Normal University , Beijing, 100048, China.
authors.forename: Lulu
authors.initials: L
authors.lastname: Tan
authors.affiliation: Department of Chemistry, Capital Normal University , Beijing, 100048, China.|Beijing Key Laboratory for Optical Materials and Photonic Devices, Capital Normal University , Beijing, 100048, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liao
mesh_terms: D002384:Catalysis; D003124:Colorimetry / Q000379:methods*; D003723:Dental Amalgam; D006046:Gold / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*
chemical_list: D006046:Gold; D003723:Dental Amalgam; D008628:Mercury