APPLICATION OF COLLISIONALLY ACTIVATED DECOMPOSITION MASS-ANALYZED ION KINETIC-ENERGY SPECTROMETRY TO A SURVEY OF SHEEP MILK FOR BENZIMIDAZOLE RESIDUES IN RELATION TO WITHDRAWAL PERIODS

A collisional spectroscopy procedure for simultaneous detection of five widely employed benzimidazole anthelmintics (laevamisole, thiabendazole, mebendazole, fenbendazole, febantel) in sheep milk was developed. The method which involves injection of crude milk extracts and selection and collision of the most abundant ionic species (M+. or fragments) obtained under electron impact ionization, is highly suitable for multi-residue analysis because of its sensitivity (limits of detection in the range of 0.6-2.8 p.p.b) and its rapidity (more than five samples per hour can be processed). The collisional approach was applied successfully for monitoring of anthelmintic residues in sheep milk.