DETERMINATION OF DICLAZURIL IN AVIAN FEED AND PREMIXES WITH GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A method is presented for the determination of the relatively new anti coccidial drug diclazuril in avian feed and premixes. The drug was ext racted from feed with acidified methanol-water, and the extracts were cleaned up by simple liquid-liquid extraction. These were then derivat ized with ethereal diazomethane, and the methyl derivatives were analy zed by gas chromatography/mass spectrometry on a bench-top instrument. An internal standard was used to enhance the reproducibility and rugg edness of the assay. The coefficients of variation for a finished feed and premix assayed 5 times each on 3 occasions were 6.6 and 6.0%, res pectively. The detection limit of the assay is about 0.02 mg/kg, which is adequate for measuring the normal inclusion rate of 1 mg/kg in fin ished feed.