title: Highly sensitive detection of melamine and its derivatives by capillary electrophoresis coupled with online preconcentration techniques.
abstract: Two kinds of online preconcentration techniques including large-volume sample stacking-sweeping and selective-exhaustive injection-sweeping (SEI-S) were employed in CE to develop a rapid, simple and sensitive method for determination of melamine (MM) and its derivatives such as ammeline (AMN), ammelide (AMD) and cyanuric acid (CA) in liquid milk products. Though the sensitivity of large-volume sample stacking-sweeping is not particularly high, it can be used to detect all the four compounds simultaneously. However, it is very difficult to improve the sensitivity of these four compounds by using single SEI-S method directly, owing to their completely different extents of protonation or deprotonation. Grouping can solve this problem perfectly. After the four compounds are divided into two groups (MM/AMN and AMD/CA), cation-SEI-S or anion-SEI-S can be applied for their online stacking. In cation-SEI-S, the detection limits for MM and AMN were both 0.01 ng/mL based on the signal-to-noise ratio of 3. In anion-SEI-S, the detection limits were 0.05 and 0.02 ng/mL for CA and AMD, respectively. Results of this study show a great potential for the SEI-S method to be a useful tool for the rapid and sensitive determination of MM and its derivatives in liquid milk products.
authors.affiliation: Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Jin
authors.forename: Lingchen
authors.initials: L
authors.lastname: Meng
authors.forename: Meixian
authors.initials: M
authors.lastname: Li
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D000818:Animals; D005591:Chemical Fractionation / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D008892:Milk / Q000737:chemistry; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D014227:Triazines / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D014227:Triazines; C004632:cyanuric acid; C067139:ammelide; C000089:ammeline; C011907:melamine