title: Room-temperature phosphorescence determination of melamine in dairy products using l-cysteine-capped Mn-doped zinc sulfide (ZnS) quantum dots.
abstract: A simple, sensitive, and precise room-temperature phosphorescence method was developed for the determination of melamine in dairy products using l-cysteine-capped Mn-doped zinc sulfide (ZnS) quantum dots as a probe. This method is based on the quenching of the phosphorescence signal of quantum dots by the interaction with melamine. Under optimum conditions, phosphorescence intensity was quenched by various concentrations of melamine in a linear range from 50 to 500ng/mL, with a detection limit of 5.95ng/mL in 10 mM phosphate buffer (pH 7.4). The relative standard deviation for 5 replicate measurements was 0.15%. The developed method was applied to dairy products to determine melamine concentrations; recovery values ranged from 96.3 to 104.7%.
authors.affiliation: Department of Food Analysis, Gazi University, 06330 Ankara, Turkey.
authors.forename: Buket Er
authors.initials: BE
authors.lastname: Demirhan
authors.affiliation: Department of Food Analysis, Gazi University, 06330 Ankara, Turkey.
authors.forename: Burak
authors.initials: B
authors.lastname: Demirhan
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey. Electronic address: eda@gazi.edu.tr.
authors.forename: H Eda Satana
authors.initials: HE
authors.lastname: Kara
mesh_terms: D000818:Animals; D003545:Cysteine; D003611:Dairy Products / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D057230:Limit of Detection; D008163:Luminescent Measurements; D008345:Manganese / Q000737:chemistry*; D045663:Quantum Dots; D012680:Sensitivity and Specificity; D013440:Sulfides; D013696:Temperature; D014227:Triazines / Q000737:chemistry*; D017967:Zinc Compounds
chemical_list: D013440:Sulfides; D014227:Triazines; D017967:Zinc Compounds; D008345:Manganese; D003545:Cysteine; C031238:zinc sulfide; C011907:melamine
keywords: melamine; milk product; quantum dot; room-temperature phosphorescence