Simultaneous Determination of Seven Mental Drugs in Feeds by Liquid Chromatography-Tandem Mass Spectrometry

A method was established for the simultaneous determination of seven mental drugs by LC-MS/MS. In this method, the conditions of appropriate extracting solvent, SPE cartridge and LC-MS/MS were optimized. The drugs were extracted with acetonitrile/water (9:1, V/V), and then purified by MCX solid-phase extraction (SPE) column. The elution was evaporated by nitrogen blow, dissolved in acetonitrile/water( 2:8, V/V) and analyzed by LC-MS/MS. The limit of detection (LOD) was 1.0 ng/g of nitrazepam, oxazepam, promethazine and chlorpromazine, and 5.0 ng/g of diazepam, perphenazine; and thioridazine. The recoveries were 53.9% - 110.2%, and RSDs were 3.4% - 18.4%. Results showed that this developed method was very reliable for the determination of seven mental drugs in feeds.