Abstract: A comprehensive analytical method based on ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of virginiamycin M1 in feeds. The sample was extracted twice by ultrasonic extraction with acetonitrile-0.2% (v/v) formic acid (8:2, v/v). The chromatographic separation was achieved with a BEH C18 column and acetonitrile-0.3%(v/v) formic acid （35:65, v/v） as the mobile phase. The identification and quantification of the analyte were carried out on electrospray ionization MS/MS in a multiple reaction monitoring (MRM) mode. The correlation coefficient (r) of virginiamycin M1 was 0.9995 in the linear range of 0.3~226.6 μg/L. The detection limit (S/N=3) and quantification limit (S/N=10) of virginiamycin M1 were 2 μg/kg and 7 μg/kg, respectively. The average spiked recoveries were in the range of 82.6% to 102.7% with the relative standard deviations (RSDs) of 0.9%~10.5%. The results demonstrate that the proposed method is simple, sensitive, repeatable and suitable for the testing of virginiamycin M1 in feeds.

Key words: feeds, ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), virginiamycin M1