title: A fast and environmental friendly analytical procedure for determination of melamine in milk exploiting fluorescence quenching.
abstract: An environmental friendly procedure was developed for fast melamine determination as an adulterant of protein content in milk. Triton X-114 was used for sample clean-up and as a fluorophore, whose fluorescence was quenched by the analyte. A linear response was observed from 1.0 to 6.0mgL(-1) melamine, described by the Stern-Volmer equation I°/I=(0.999±0.002)+(0.0165±0.004) CMEL (r=0.999). The detection limit was estimated at 0.8mgL(-1) (95% confidence level), which allows detecting as low as 320μg melamine in 100g of milk. Coefficients of variation (n=8) were estimated at 0.4% and 1.4% with and without melamine, respectively. Recoveries to melamine spiked to milk samples from 95% to 101% and similar slopes of calibration graphs obtained with and without milk indicated the absence of matrix effects. Results for different milk samples agreed with those obtained by high performance liquid chromatography at the 95% confidence level.
authors.affiliation: Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, P.O. Box 96, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Carina F
authors.initials: CF
authors.lastname: Nascimento
authors.affiliation: Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, P.O. Box 96, 13400-970 Piracicaba, SP, Brazil.
authors.forename: Diogo L
authors.initials: DL
authors.lastname: Rocha
authors.affiliation: Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, P.O. Box 96, 13400-970 Piracicaba, SP, Brazil. Electronic address: frprocha@cena.usp.br.
authors.forename: Fábio R P
authors.initials: FR
authors.lastname: Rocha
mesh_terms: D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000737:chemistry; D014227:Triazines / Q000032:analysis*
chemical_list: D014227:Triazines; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40; C011907:melamine
keywords: Adulteration; Cloud point extraction; Fluorescence; Melamine; Milk; Triton X-114