Determination of New Veterinary Drug Tulathromycin Residues in Pork by High Performance Liquid Chromatography Tandem Mass Spectrometry
A method based on high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) with symmetryC8 column as the separation column has been developed for the determination of tulathromycin residues in pork.The analyte was extracted with methanol and 0.1% phosphoric acid(70:30,V/V) solution from homogenized samples,and then the extract was filtered and cleaned by PCX solid phase extraction cartridge.Quantification of the tulathromycin was achieved by HPLC-MS/MS with multiple reactions monitoring using internal standard method.The detection limits of HPLC-MS/MS for the tulathromycin was 5.0 μg/kg.The average recovery varies from 93.1% to 105.5% at the spiked level of 10,20 and 50 μg/kg,the within-run RSD of the method was 1.5%-4.6%,and the between-run RSD of the method was1.8%-5.6%.