Objective: To develop a method for simultaneous determination of avermectin (AVM) and ivermectin (IVM) in swine muscular tissues using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).
Methods: The AVM and IVM were extracted with acetonitrile, cleaned with basic alumina solid phase extraction cartridges, separated through C8 column, and then detected by mass spectrometry in positive ion mode with multiple reaction monitoring (MRM) using an electrospray ionization interface, with quantitative ion pair of 890.4/305.3 and 892.5/307.3 for AVM and IVM, respectively.
Results: The linear ranges for both AVM and IVM were between 5 microg/L and 100 microg/L, with a correlation coefficient of 0.9999. The detection limit was 2.0 microg/kg. The recoveries at the spiked concentration of 2 microg/kg, 10 microg/kg and 20 microg/kg ranged from 77.4% to 83.1% for AVM and 77.2% to 84.8% for IVM, with relative standard deviation (RSD) ranging from 8.7% to 11.7% for AVM and 6.3% to 10.3% for IVM, respectively. No AVM and IVM residues were detected in samples taken from Chengdu markets.
Conclusion: A HPLC-MS/MS method was successfully developed for determining AVM and IVM in swine muscular tissues, which is simple, sensitive and precise and can meet both domestic and international requirements.