Determination of Valnemulin Residues in Chicken Tissues by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A liquid chromatography with electrospray ionization tandem mass spectrometry detection (LC ESI MS/MS) method for the determination of valnemulin residues in chicken tissues was developed.The analyte was extracted with acetonitrile and the extract was cleaned up by the Strata-X-C solid phase extraction column.Chromatographic separation of valnemulin was performed in isocratic mode,on a C18 column using acetonitrile and 0.1% formic acid aqueous solution (35:65,V/V).Qualitation and quantification of valnemulin were achieved with multiple reaction monitoring (MRM) in positive electrospray ionization.Matrix-matched calibration standard was used for quantification.The calibration curve was good linear from 5(7.5) to 500 μg/kg with the correlation coefficient of 0.998.The limits of detection (LOD) were 4 μg/kg in liver tissue and 2.5 μg/kg in others,and the limits of quantification (LOQ) were 7.5 and 5.0 μg/kg,respectively.The mean recoveries varied from 78.5% to 104.0% at the three spiked levels of 5(7.5),50,and 500 μg/kg.The intra-day relative standard deviation (RSD) and inter-day RSD were in the range of 1.2%-9.8%,and 3.7%-13.2%,respectively.