A method was established for the simultaneous determination of vancomycin and norvancomycin residues in milk and dairy products by solid-phase extraction and ultra performance liquid chromatography coupled with tandem mass spectrometry(UPLC-MS/MS).The sample was extracted with a mixed solution of acetonitrile and water.Then the protein was precipitated with trichloroacetic acid, the fat and other impurities were eliminated with dichloromethane.The extration solution was purified with Strata-X-C solid phase extraction(SPE) column.The target compounds were separated on a reversed phase column by gradient elution of acetonitrile and 0.1% formic acid water solution,and then detected with positive electrospray ionization under multiple reaction monitoring(MRM) mode.The SPE conditions and UPLC-MS/MS parameters were optimized.Under the optimized conditions,the calibration curves for two target compounds were linear in the range of 4-5 000 μg/L with correlation coefficients(r2) greater than 0.99.The average recoveries of blank matrix sample at three spiked levels of 15,60, 150 μg/kg were all more than 80%,and the relative standard deviations(RSDs)were less than 5%.The limits of detection(LODs)for vancomycin and norvancomycin were 0.5 μg/kg and 0.8 μg/kg,respectively.The limits of quantitation(LOQs)were 2.0 μg/kg and 3.0 μg/kg,respectively.The method was practical,accurate and sensitive,and was suitable for the determination of vancomycin and norvancomycin in milk and dairy products.
关键词
液相色谱-串联质谱固相萃取乳和乳制品万古霉素去甲万古霉素
Keywords
UPLC-MS/MSsolid phase extractionmilk and dairy productsvancomycinnorvancomycin