Multiresidue method for the detection of tranquillisers, xylazine, and a β-blocker in animal production by liquid chromatography-tandem mass spectrometry

Tranquillisers are often used in animal production, especially in pigs to calm them before transport to the slaughterhouse. The use of certain substances (derived from phenothiazine) is totally prohibited, whilst other compounds (butyrophenone and β-blockers) are regulated through the establishment of MRLs. A physico-chemical detection method based on liquid chromatography-tandem mass spectrometry is described. Validation was carried out according to the criteria laid down in Directive 2002/657/EC. The method was also used to detect and quantify these substances in treated animals.