title: Simultaneous determination of urea and melamine in milk powder by nonlinear chemical fingerprint technique.
abstract: This paper proposed a nonlinear chemical fingerprint method for simultaneous determination of urea and melamine in milk powder using "H++Ce4++BrO3-+malonic acid" as reaction system. A multiple linear relationship was obtained between the adulterants content in milk powder and inductive time of corresponding mixed milk powder. System analysis model established with classical least squares (CLS) method was then used to calculate the content of urea and melamine in milk powder. The method was successfully applied to milk powder samples and had good recoveries in the range of 99.17-100.25%, with the relative standard deviation (RSD) in the range of 0.60-4.12%. The limits of detection for urea and melamine were 0.33μg·g-1and 0.05μg·g-1, respectively. The limits of quantification were 1.11μg·g-1and 0.18μg·g-1, respectively. The results indicated that the new method was feasible and had the advantages of low cost, simple operation and without pretreatment of samples.
authors.affiliation: College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Weiyang University Circle, Xi'an 710021, PR China; Mathematical and Sciences College, LouYang Normal University, University Street, Luoyang 471022, PR China. Electronic address: mayongjie113@163.com.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Ma
authors.affiliation: College of Food and Biological Engineering, Shaanxi University of Science and Technology, Weiyang University Circle, Xi'an 710021, PR China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Dong
authors.affiliation: Mathematical and Sciences College, LouYang Normal University, University Street, Luoyang 471022, PR China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Bao
authors.affiliation: College of Food and Biological Engineering, Shaanxi University of Science and Technology, Weiyang University Circle, Xi'an 710021, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Institute of Product Quality Supervision and Inspection in Shaanxi Province, Xianning West Road 30, Xi'an 710048, PR China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Fan
mesh_terms: D000148:Acids, Noncarboxylic; D000818:Animals; D002563:Cerium; D055664:Electrochemical Techniques / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D057230:Limit of Detection; D008314:Malonates; D008892:Milk / Q000737:chemistry*; D011208:Powders / Q000737:chemistry; D014227:Triazines / Q000032:analysis*; D014508:Urea / Q000032:analysis*
chemical_list: D000148:Acids, Noncarboxylic; D008314:Malonates; D011208:Powders; D014227:Triazines; D002563:Cerium; D014508:Urea; C531577:bromic acid; C030290:malonic acid; C011907:melamine
keywords: Classical least squares method; Melamine; Multiple linear regression model; Nonlinear chemical fingerprint; Urea