title: Single Gold Nanoparticle-Based Colorimetric Detection of Picomolar Mercury Ion with Dark-Field Microscopy.
abstract: Mercury severely damages the environment and human health, particularly when it accumulates in the food chain. Methods for the colorimetric detection of Hg(2+) 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 Hg(2+) 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 Hg(2+) 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 Hg(2+) 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.
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liu
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Zhangjian
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Chenghua
authors.initials: C
authors.lastname: Zong
authors.affiliation: Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Chemical Engineering, Jiangsu Normal University , Xuzhou, Jiangsu 221116, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Gai
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003124:Colorimetry; D060766:Drinking Water / Q000032:analysis; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007477:Ions / Q000737:chemistry; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008853:Microscopy
chemical_list: D060766:Drinking Water; D007477:Ions; D006046:Gold; D008628:Mercury