title: Comparison of different solid-phase extraction materials for the determination of fluoroquinolones in chicken plasma by LC-MS/MS.
abstract: Fluoroquinolones are synthetic antibiotics which are frequently used in veterinary medicine e.g. for the treatment of poultry. Their specific importance is based on the fact that they are regarded as antibiotics of last resort because of their broad spectrum of action against Gram-negative and -positive bacteria. Here, a new and sensitive method for the simultaneous determination of four fluoroquinolones (marbofloxacin, ciprofloxacin, enrofloxacin and difloxacin) in chicken plasma by LC-MS/MS was developed. Solid-phase extraction was chosen for sample preparation because a selective sample clean-up is combined with an effective extraction. Various solid-phase extraction materials including polymer-based reversed-phase, silica-based reversed-phase and mixed-mode sorbents were compared. Selection criteria were analyte recovery, sample extract purity and economical aspects (analysis time and elution solvent volume). Best recoveries and minimized elution solvent volumes were achieved using polymeric reversed-phase cartridges. However, post-column infusion experiments revealed that the analysis is influenced by co-eluting matrix components. Hence, a combination of a mixed-mode anion-exchange cartridge and a mixed-mode cation-exchange cartridge was used as final extraction method. This method yield slightly lower analyte recoveries compared to polymeric-reversed-phase cartridges but exhibit no matrix effects. Recoveries of spiked chicken plasma ranged from 61.9% to 84.8% with an inter-day precision of generally less than 12%. LODs are between 0.03 and 0.05μg/L; LOQs are between 0.08 and 0.16μg/L. Maximum plasma concentrations of chickens medicated with an enrofloxacin dosage of 3mg/kg bodyweight were 38.9μg/L for enrofloxacin and 3.3μg/L for its main metabolite ciprofloxacin.
authors.affiliation: Justus Liebig University Giessen, Institute of Food Chemistry and Food Biotechnology, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Janusch
authors.affiliation: University of Veterinary Medicine Hannover, Foundation, Institute of Pharmacology, Toxicology and Pharmacy, Buenteweg 17, 30559 Hannover, Germany.
authors.forename: Gesine
authors.initials: G
authors.lastname: Scherz
authors.affiliation: Justus Liebig University Giessen, Institute of Food Chemistry and Food Biotechnology, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Siegrun A I
authors.initials: SA
authors.lastname: Mohring
authors.affiliation: University of Veterinary Medicine Hannover, Foundation, Institute of Pharmacology, Toxicology and Pharmacy, Buenteweg 17, 30559 Hannover, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Stahl
authors.affiliation: Justus Liebig University Giessen, Institute of Food Chemistry and Food Biotechnology, Heinrich-Buff-Ring 58, 35392 Giessen, Germany. Electronic address: Gerd.Hamscher@lcb.chemie.uni-giessen.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hamscher
mesh_terms: D000818:Animals; D002645:Chickens; D002853:Chromatography, Liquid / Q000379:methods*; D024841:Fluoroquinolones / Q000097:blood* / Q000302:isolation & purification; D057230:Limit of Detection; D016014:Linear Models; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D024841:Fluoroquinolones
keywords: Chicken; Fluoroquinolones; LC-MS/MS; Plasma; Solid-phase extraction