Determination of Colistin,Bacitracin and Virginiamycin Multiresidues in Animal Tissue by Liquid Chromatography-Tandem Mass Spectrometry

A method was established to simultaneously detect colistin,bacitracin,virginiamycin residues in animal tissues,such as muscle,liver and kidney,by liquid chromatography tandem mass spectrometry.The samples were extracted by methanol-0.1% formic acid,and cleaned up by Oasis HLB solid phase extraction column.The analytes were separated by liquid chromatography and determined by liquid chromatography coupled to tandem mass spectrometry under electrospray ion and multiple reaction monitor(MRM) mode.The results indicated that the detection limits of colistin,bacitracin and virginiamycin were 25,50 and 20 μg/kg,respectively,and their average recoveries were 89%-98%,90%-99% and 92%-100%,respectively.The relative standard deviations(RSDs)ranged from 1.91% to 9.81%.The method has the advantage of simplicity,sensitivity and repeatability,and is suitable for simultaneous determination of peptides antibiotics in animal tissues.The technical indicators of methods could meet the request of peptide antibiotic residue testing at home and abroad.