Abstract: An ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method was established for determination of acetylisovaleryltylosin in swine liver.The target drug was extracted from sample with EDTA-McIlvaine's and the extract was cleaned up on an Oasis HLB cartridge. Separation was performed on C₁₈ column with acetonitrile-0.1% formic acid(7∶3,V/V) as the mobile phase. The identification of drug was carried out by positive electrospray ionization (ESI+) under selective ion monitoring mode (SIM). The calibration curve of the drug showed excellent linearity within the range of 5 to 2000 ng/mL and the correlation coefficient was more than 0.99. The average recoveries from spiked swine liver at levels of 5 to 500 μg/kg ranged from 84.9% to 88.1%, the intra-day coefficient variation was in range of 8.2% to 15.1% and inter-day coefficient variation was in range of 14.7% to 16.5%. The limit of detection (LOD) was 0.76 μg/kg and limit of quantification (LOQ) was 2.51 μg/kg.The method was accurate and sensitive, so it could be used for determining of acetylisovaleryltylosin in swine liver.

Key words: UPLC-MS/MS; swine liver; acetylisovaleryltylosin; residue