title: Analysis of Six β-Lactam Residues in Milk and Egg by Micellar Electrokinetic Chromatography with Large-Volume Sample Stacking and Polarity Switching.
abstract: A new micellar electrokinetic chromatography method with large-volume sample stacking and polarity switching was developed to analyze amoxicllin, cephalexin, oxacillin, penicillin G, cefazolin, and cefoperazone in milk and egg. The important parameters influencing separation and enrichment factors were optimized. The optimized running buffer consisted of 10 mM phosphate and 22 mM SDS at pH 6.7. The sample size was 1.47 kPa × 690 s, the reverse voltage was 20 kV, and the electric current recovery was 95%. Under these optimum conditions, the enrichment factors of six β-lactams were 193-601. Their LODs were <0.26 ng/g, and LOQs were all 2 ng/g, which was only 1/50-1/2 of the maximum residual limits demanded by U.S. and Japanese regulations. The intraday and interday RSDs of method were lower than 3.70 and 3.91%, respectively. The method can be applied to determine these six antibiotic residues in egg and milk.
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Yu-Xiu
authors.initials: YX
authors.lastname: Shao
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Guan-Hua
authors.initials: GH
authors.lastname: Chen
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Rou
authors.initials: R
authors.lastname: Fang
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Ling-Xiao
authors.initials: LX
authors.lastname: Yi
authors.affiliation: College of Food and Bioengineering, Jiangsu University , Zhenjiang 212013, China.
authors.forename: Hong-Lian
authors.initials: HL
authors.lastname: Meng
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D004350:Drug Residues / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D010063:Ovum / Q000737:chemistry*; D047090:beta-Lactams / Q000032:analysis*
chemical_list: D047090:beta-Lactams
keywords: large-volume sample stacking; micellar electrokinetic chromatography; polarity switching; β-lactam residues