Abstract: An analytical method for the simultaneous determination of 3 tetracyclines, 10 sulfonamides and 8 quinolones in chicken livers by ultra performance liquid chromatography coupled with tandem quadrupole mass spectrometry (UPLC-MS/MS) in positive ion mode with multiple reaction monitoring (MRM) has been developed and validated. A total of 2 g homogenized sample of chicken livers was placed in a 50 mL polypropylene tube, and 1 mL of McIlvaine buffer and 4 mL of acetonitrile were added. After stirring and centrifuging for 5 min at 4000 r/min, the supernatant was collected and the remains was extracted by 5 mL acetonitrile. The supernatant was merged together and evaporated to dryness under a steam of nitrogen at 60 ℃. The residue was dissolved with 4 mL of phosphoric acid-triethylamine buffer-acetonitrile (85:15, v/v) and 4 mL of n-hexane. After stirring for 1 min and centrifuging for 5 min at 4000 r/min, the under layer solution was analyzed using UPLC-MS/MS. The satisfactory recoveries (66.8%~128.5%) of all the veterinary drugs were demonstrated at spiked levels of 5, 10 and 50 μg/kg with the overall relative standard deviations (RSDs) for intra-day and inter-day of the 21 analytes less than 20.5%. The limit of detection (LOD) and the limit of quantification (LOQ) were 2 μg/kg and 5 μg/kg, respectively for each drug. This method has good stability, lower detection limits and can be used as a conclusive evidence method of these drug residues in chicken livers.

Key words: chicken livers , multiresidue, quinolones, sulfonamides, tetracyclines, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)