title: Rapid determination of melamine in milk using water-soluble CdTe quantum dots as fluorescence probes.
abstract: Water-soluble CdTe quantum dots of different sizes capped with thioglycolic acid (TGA-CdTe QDs) were synthesised via a microwave-assisted method. It was found that melamine could quench the fluorescence emission of TGA-CdTe QDs in aqueous solution. Based on this, a novel method for the determination of melamine has been developed. Under optimum conditions, the fluorescence intensity of TGA-CdTe QDs versus melamine concentrations gave a linear response according to the Stern-Volmer equation. The proposed method has been successfully used to detect melamine in liquid milk with a detection limit of 0.04 mg L⁻¹, and the whole process including sample pre-treatment could be accomplished within 30 min. The obvious merits provided by this method, such as simplicity, rapidity, low cost and high sensitivity would make it promising for on-site screening of melamine adulterant in milk products. The possible mechanism involved in the interaction of melamine with TGA-CdTe QDs is discussed.
authors.affiliation: Department of Food Quality and Safety, College of Quartermaster Technology, Jilin University, Changchun, China.
authors.forename: Minwei
authors.initials: M
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Ping
authors.forename: Xianyi
authors.initials: X
authors.lastname: Cao
authors.forename: Hongkun
authors.initials: H
authors.lastname: Li
authors.forename: Fengrui
authors.initials: F
authors.lastname: Guan
authors.forename: Chunyan
authors.initials: C
authors.lastname: Sun
authors.forename: Jingbo
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry*; D002138:Calibration; D005240:Feasibility Studies; D005456:Fluorescent Dyes / Q000737:chemistry*; D005506:Food Contamination; D005513:Food Inspection / Q000379:methods; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry; D013997:Time Factors; D014227:Triazines / Q000032:analysis*
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D013864:Thioglycolates; D014227:Triazines; C017487:2-mercaptoacetate; C011907:melamine; D013691:Tellurium; C028337:cadmium telluride