title: Visual detection of Hg2+ based on Hg(2+)-xanthine complex preventing aggregation of gold nanoparticles.
abstract: Xanthine, which can specifically bind with mercury ion (Hg2+) to form xanthine-Hg(2+)-xanthine complex, was used as Hg2+ binding molecule in this paper. In the absence of Hg2+, imide group of xanthine easily adsorbs onto the surface of gold nanoparticles (AuNPs) and induces aggregation of AuNPs, resulting in a blue color. In the presence of Hg2+, however, the selective binding of xanthine with Hg2+ prevents the AuNPs against xanthine induced aggregation, resulting in a visible color change from blue to red depend on the concentration of Hg2+. Therefore, taking advantage of this phenomenon, a simple, cost-effective and rapid method can be established for Hg2+ visual detection. This method allows the detection of Hg2+ in the range of 0.075-4.0 microM with a detection limit (3sigma/slope) of 15 nM, and exhibits a high selectivity toward Hg2+ over other metal ions. Particularly, as low as 0.5 microM Hg2+ can be easily detected by the naked eye without using any complicated or expensive instruments.
authors.forename: Wen Dan
authors.initials: WD
authors.lastname: Pu
authors.forename: Hua Wen
authors.initials: HW
authors.lastname: Zhao
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
authors.forename: Li Ping
authors.initials: LP
authors.lastname: Wu
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
mesh_terms: D003116:Color; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D008628:Mercury / Q000032:analysis* / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D019820:Xanthine / Q000737:chemistry*
chemical_list: D019820:Xanthine; D006046:Gold; D008628:Mercury