| A simple,rapid and sensitive method was developed for the simultaneous determination of vancomycin and norvancomycin in pork by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The sample was supersonically extracted with a mixture of 0.1% formic acid-acetonitrile(7∶3),and cleaned up with hexane(acetonitrile saturated) and a LC-C18 solid phase extraction cartridge.The separation of two targets was carried out on a Waters UPLC BEH C18 column by gradient elution with 0.1% formic acid-acetonitrile as mobile phase.With positive electrospray ionization(ESI+) and multiple reaction monitoring(MRM),the two compounds were identified with retention time and ion ratio.The results showed that the two compounds displayed excellent peak shapes within 3 min with correlation coefficients more than 0.99.The limits of detection(LOD,S/N=3) of vancomycin and norvancomycin were 0.5 μg/kg and 0.3 μg/kg,respectively.The average recoveries were between 80% and 88% for the target compounds at spiked levels of 1-20 μg/kg.The intra-day RSDs were no more than 13.4%,and the inter-day RSDs were no more than 12.5%.The method was accurate and sensitive,and was suitable for the quantitative and qualitative analyses of glycopeptide antibiotics in pork sample. |