Simultaneous determination and confirmation of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine in chicken muscle by liquid chromatography–tandem mass spectrometry

A reliable and sensitive liquid chromatography–electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS) confirmation method has been developed for the simultaneous determination of chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF), and florfenicol amine (FFA) in chicken muscle. Samples were extracted with basic ethyl acetate, defatted with hexane, and cleaned up on Oasis MCX cartridges. LC separation was achieved on a XTerra C18 column with gradient elution using a mobile phase composed of acetonitrile and water at a flow rate of 0.20 mL/min. The analysis was carried out on a triple–quadrupole tandem mass spectrometer in the multiple reaction monitoring (MRM) mode via electrospray interface operated in the positive and negative ionization modes, with deuterated chloramphenicol-d5 (d5-CAP) as the internal standard. The method validation was performed according to the criteria of Commission Decision 2002/657/EC. Four identification points were obtained for each analyte with one precursor ion and two product ions. Limits of detection (LODs) were 0.1 μg/kg for CAP, 0.2 μg/kg for FF and 1 μg/kg for TAP and FFA in chicken muscle. Linear calibration curves were obtained over concentration ranges of 0.3–20 μg/kg for CAP, 0.5–20 μg/kg for FF and 3–100 μg/kg for TAP and FFA in tissues. Mean recoveries of the 4 analytes ranged from 95.1% to 107.3%, with the corresponding intra- and inter-day variation (relative standard deviation, R.S.D.) less than 10.9% and 10.6%, respectively. The decision limit (CCα) and detection capability (CCβ) of the method were also reported.