title: Colorimetric assay of melamine based on the aggregation of gold nanoparticles.
abstract: Under certain acidic condition, thioglycolic-acid-modified gold nanoparticles (Au-NPs) can react with melamine, resulting in the aggregation of Au-NPs through electrostatic interactions between -COO(-) groups on the surface of Au-NPs and -NH3+ groups of melamine. The aggregation extent depends on the concentration of melamine, which can be validated by SEM imaging and UV-vis spectra. During the aggregation procedure, color change can be observed. Based on the color change, a simple, fast, cheap and visual colorimetric method of detecting melamine is developed, which can be effectively applied to detect melamine in milk powder and develop a new diagnostic kit of melamine.
authors.affiliation: Department of Chemistry, Third Military Medical University, Chongqing 400038, P. R. China.
authors.forename: Su Fen
authors.initials: SF
authors.lastname: Shen
authors.forename: Hua Wen
authors.initials: HW
authors.lastname: Zhao
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.forename: Li Ping
authors.initials: LP
authors.lastname: Wu
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
mesh_terms: D000143:Acids / Q000737:chemistry; D003116:Color; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011208:Powders; D012996:Solutions; D013057:Spectrum Analysis; D014227:Triazines / Q000032:analysis*
chemical_list: D000143:Acids; D011208:Powders; D012996:Solutions; D014227:Triazines; D006046:Gold; C011907:melamine