title: Simultaneous determination of six penicillins in cows' raw milk by a multiresidue high-performance liquid chromatographic method.
abstract: A high-performance liquid chromatographic method based on C18 solid-phase extraction and ultraviolet detection at 323 nm of analytes derivatized with benzoic anhydride and 1,2,4-triazole mercuric chloride solution was developed for the simultaneous determination of amoxicillin, penicillin G (benzylpenicillin), ampicillin, oxacillin, cloxacillin and dicloxacillin residues in raw milk. The detection limit of the method was 1.3 microg/l for penicillin G; 1.4 microg/l for amoxicillin, oxacillin and cloxacillin, 1.5 microg/l for ampicillin and 2.7 microg/l for dicloxacillin. The mean recovery was 95-102% for amoxicillin, penicillin G and ampicillin, 92-98% for oxacillin and cloxacillin and 87-94% for dicloxacillin, measured by using an internal standard. The relative repeatability standard deviation was 4-9% on level 4-15 micro/l, respectively, 2-7% on level 30-40 microg/l.
authors.affiliation: Steins Laboratorium, Brørup, Denmark.
authors.forename: L K
authors.initials: LK
authors.lastname: Sørensen
authors.forename: B M
authors.initials: BM
authors.lastname: Rasmussen
authors.forename: J O
authors.initials: JO
authors.lastname: Boison
authors.forename: L
authors.initials: L
authors.lastname: Keng
mesh_terms: D000658:Amoxicillin / Q000032:analysis; D000667:Ampicillin / Q000032:analysis; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003023:Cloxacillin / Q000032:analysis; D004009:Dicloxacillin / Q000032:analysis; D004350:Drug Residues / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D010068:Oxacillin / Q000032:analysis; D010400:Penicillin G / Q000032:analysis; D010406:Penicillins / Q000032:analysis*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D010406:Penicillins; D000667:Ampicillin; D000658:Amoxicillin; D004009:Dicloxacillin; D003023:Cloxacillin; D010400:Penicillin G; D010068:Oxacillin