Rapid Determination of Tranquillizers Residues in Swine Urine by Liquid Chromatography-Tandem Mass Spectrometry

A method was developed for the determination residual tranquillizers (xylazine, azaperone, droperidol, haloperidol, estazolam, chlorpromazine, perphenazine, nitrazepam, oxazepam, and diazepam) in swine urine by liquid chromatography-tandem mass spectrometry. Samples were directly purified through C-18 cartridge after centrifugation. Then the eluate was dried under nitrogen and residues were dissolved in 0.1% formic acid solution. The samples were analyzed by LC-MS/MS on an Eclipse XDB-C-18 column with a mixture of acetonitrile and 0.1% formic acid solution as the mobile phase. The samples were quantified with the matrix standard calibration curve method. Good linearities were obtained for the ten tranquillizers at the concentration of 5 - 200 mu g/L with the linear relative coefficient more than 0.99. The recoveries for the ten tranquillizers in swine urine were 74.6% - 115.0% at the fortified levels of 1.0 - 10.0 mu g/L, with the limit of detection of 0.11 - 0.52 mu g/L and the limit of quantitation of 0.20 - 0.91 mu g/L. The relative standard deviations were less than 15.0%.