Rapid and Simultaneous Determination of Several Classes of Veterinary Drug Residues in Milk by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

An analytical method based on ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) was developed for the rapid and simultaneous determination of 11 veterinary drug residues in milk.The analytes were extracted from the sample by ultrasonic bath in acetonitrile and centrifuged.The supernatant liquid was diluted 10 times with mobile phase and filtered with a 0.2 μm micro filter,and then analyzed by UPLC-MS/MS.Under the optimized conditions,the calibration curves for 11 veterinary drugs were linear with their correlation coefficients higher than 0.998,and the limits of quantitation(LOQ,S/N=10) ranged from 0.3 μg/kg to 15 μg/kg.The mean recoveries at three spiked levels were between 81% and 117% with relative standard deviations of 0.6%-10.2%.The proposed method was successfully applied in the determination of veterinary drug residues in milk with satisfactory results.