Detection of Valnemulin Residues in Pork by Ultra Performance Liquid Chromatography Tandem Mass Spectrometry

A method was developed for quantitative and qualitative determination of valnemulin(VLM) hydrochloride residue in porcine muscles by using ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The samples were extracted with acetonitrile at the same time adding hexane to remove the fat,then centrifuged and removed the hexane,just evaporated the part of acetonitrile.The residue was dissolved with acetonitrile-0.1% formic acid(40∶60,V∶V).Chromatographic separation of the valnemulin was performed on a C18 column using formic acid 0.1% in acetonitrile and formic acid 0.1% in water by gradient elution.The LOD and LOQ of this method were 10 μg/kg and 20 μg/kg,respectively.Average analyte recoveries were more than 92.60% in replica sets of porcine muscles at three different concentrations(20、50、100 μg/kg).Inter-day RSD was from 1.31% to 6.80%,and intra-day RSD was from 3.02% to 4.60%.The results suggested that this method was a robust and effective method for determination of valnemulin residues in pork.