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Determination of cypromazine and its metabolite melamine in milk by cation‐selective exhaustive injection and sweeping‐capillary micellar electrokinetic chromatography
Author(s) -
Li Xuegang,
Hu Jiwei,
Han Heyou
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201000559
Subject(s) - chromatography , chemistry , micellar electrokinetic chromatography , metabolite , melamine , detection limit , capillary electrophoresis , matrix (chemical analysis) , acetonitrile , biochemistry , organic chemistry
In this study, we described a high‐sensitive on‐line preconcentration method for cypromazine (CYP) and melamine (MEL) analysis using cation‐selective exhaustive injection (CSEI) combined with sweeping‐MEKC. The optimum conditions of on‐line concentration and separation were discussed. The BGE contained 100 mM SDS, 50 mM phosphoric acid (pH=2.0) and 15% acetonitrile (v/v). The sample was injected at 10 kV for 600 s, separated at −20 kV, and detected at 210 nm. The sensitivity enhancements were 6222 for CYP and 9179 for MEL. The linear dynamic ranges were 0.4−25 ng/mL for CYP ( r =0.9995) and 0.2−12 ng/mL for MEL ( r =0.9991). The LODs (signal‐to‐noise ratio, 3) were 43.7 and 23.4 pg/mL for CYP and MEL, respectively. The proposed method was applied to analyze CYP and MEL in dairy products pretreated using off‐line SPE to minimize the influence of the matrix. The recoveries of CYP and MEL were satisfactory (ca. 74–83%). The experimental results suggest that the CSEI‐sweeping‐MEKC method is feasible for the application to simultaneously detect trace levels of CYP and its metabolite MEL in real milk samples.