title: A determinative and confirmatory method for ceftiofur metabolite desfuroylceftiofur cysteine disulfide in bovine kidney by LC-MS/MS.
abstract: Ceftiofur is a cephalosporin β-lactam antibiotic widely used for treating certain bacterial infections in beef and dairy cattle. The regulatory HPLC-UV method for ceftiofur residues in animal tissues is time consuming and non-specific. Additionally, because the regulatory method involves chemical reactions to convert the metabolites into a single moiety, it is virtually impossible to incorporate the procedure into a multi-residue method. Ceftiofur residue violations in beef and dairy cattle have been frequently reported and therefore an improved method is needed. Herein we report a rapid and sensitive LC-MS/MS method for the determination and confirmation of ceftiofur metabolite, desfuroylceftiofur cysteine disulfide (DCCD), in bovine kidney tissue. The new method utilizes a simple extraction with phosphate buffer followed by SPE cleanup. A deuterated internal standard was synthesized and used for quantitation. The matrix-based calibration curve was linear from 25 to 2000 ng/g. The average accuracy for control kidney samples from six different sources fortified at 50-1000 ng/g was 97.7-100.2% with CV ≤ 10.1%. The limit of confirmation was 50 ng/g.
authors.affiliation: Center for Veterinary Medicine, U.S. Food and Drug Administration, 8401 Muirkirk Road, Laurel, MD 20708, USA. shixiafeng@fda.hhs.gov
authors.forename: Shixia
authors.initials: S
authors.lastname: Feng
authors.forename: Chaitali
authors.initials: C
authors.lastname: Chattopadhaya
authors.forename: Philip
authors.initials: P
authors.lastname: Kijak
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Chiesa
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Tall
mesh_terms: D000818:Animals; D002417:Cattle; D002511:Cephalosporins / Q000032:analysis* / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D004350:Drug Residues / Q000032:analysis* / Q000378:metabolism; D007668:Kidney / Q000737:chemistry* / Q000378:metabolism; D016018:Least-Squares Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D002511:Cephalosporins; C063324:desfuroylceftiofur; C053503:ceftiofur; D003545:Cysteine