title: Research on degradation of penicillins in milk by β-lactamase using ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry.
abstract: The degradation of penicillin G, penicillin V, and ampicillin in milk in the presence of β-lactamase was investigated by ultra-performance liquid chromatography coupled with electrospray ionization-time-of-flight mass spectrometry. Degradation products of the 3 penicillins in milk were identified based on the fact that the metabolites or degradation products contain a substructure of penicillin, and their degradation pathways in acidic milk in presence of β-lactamase were developed. The influence of factors on the degradation was investigated, including β-lactamase dosage, temperature, time, and acidity. The ratio of the 2 degradation products (penicilloic acid and penilloic acid) is different at different temperatures and pH. Penicilloic acid was the dominant species obtained at pH 6 under 40°C, but, being unstable, it could not be used as a standard for accurate analysis of penicilloic acid, and also could not be used as target for detection of penicillins in milk. Penilloic acid was the dominant species obtained at pH 2 above 40°C; it was stable and could be used as a standard for quantitative analysis and as target for detecting whether penicillins were used in milk.
authors.affiliation: College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002, China; Hebei Chemical & Pharmaceutical College, Shijiazhuang 050026, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Li
authors.affiliation: Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang 050051, China.
authors.forename: Chunhai
authors.initials: C
authors.lastname: Guo
authors.affiliation: Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang 050051, China.
authors.forename: Lianfeng
authors.initials: L
authors.lastname: Ai
authors.affiliation: Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang 050051, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Dou
authors.affiliation: Hebei Chemical & Pharmaceutical College, Shijiazhuang 050026, China.
authors.forename: Guizhen
authors.initials: G
authors.lastname: Wang
authors.affiliation: College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002, China. Electronic address: hanwen@hbu.cn.
authors.forename: Hanwen
authors.initials: H
authors.lastname: Sun
mesh_terms: D000667:Ampicillin / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000737:chemistry*; D010400:Penicillin G / Q000378:metabolism*; D010404:Penicillin V / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature; D013997:Time Factors; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000667:Ampicillin; D001618:beta-Lactamases; D010400:Penicillin G; D010404:Penicillin V
keywords: degradation; milk; penicillin; β-lactamase