Determination of ten sedative residues in pork and kidney by ultra performance liquid chromatography-tandem mass spectrometry

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the determination of methaqualone, chloropromazine, promethazine, diazepam, nitrazepam, oxazepam, temazepam, midazolam, triazolam and Zolpidem residues in pork and kidney. After enzymolysis, the samples were extracted by ethyl acelate and tert-butyl methyl ether, separately. The separation of the ten sedatives was performed on a Waters Acquity UPLC system with a BEH C-18 column. The mobile phases were acetonitrile containing 0. 1% formic acid) and water (1) containing 0. 1% formic acid) at a flow rate of 0. 3 mL/min. The electrospray was operated in the positive ionization mode and the ten sedatives were identified by multiple reaction monitoring (MRM) mode. The method of matrix-matched standard solution was adopted as the quantitative method. The calibration curves showed good linearity within the concentrations of 2 - 100 mu/L with the correlation coefficients r > 0. 998. The limits of detection of the ten sedatives were 0. 5 mu/kg > and the limit of quantification was 1 mu/kg. The recoveries of the ten sedatives were 64. 5% - 111. 4% at the spiked levels of 2, 5 and 10 mu/kg. The relative standard deviations of infra- and inter-day coefficients of variation were both less than 15%. This method is simple, sensitive and accurate in the determination of sedative residues.