Abstract: A method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) had been developed for the determination of vancomycin in feeds. The analyte was extracted with phosphate buffer -acetonitrile(85:15,V/V),and cleaned by strong cation exchange solid phase extraction cartridge. Quantification of the analyte was achieved by UPLC-MS/MS with multiple reaction monitoring (MRM) using external standard method. The calibration curves of vancomycin were linear over the concentration ranges of 25 to 1000 ng/mL in different matrix. Detection and quantification limits of the method for the analyte were 0.05 and 0.1 mg/kg in feeds. The average recoveries ranged from 86.7% to 117.1% at the spiked level of 0.1 to 100 mg/kg in feeds. The inter-run and between-run relative standard deviation was 1.0% to 17.4% and 2.9% to 10.1%,respectively. The method was reliable,sensitive and reproducibility,its performance could meet the requirements of the domestic and international legislation.The method adapted to the determination of vancomycin in feeds.

Key words: feeds; vancomycin; UPLC-MS/MS