Determination of Diclazuril in Avian Feed and Premixes with Gas Chromatography/Mass Spectrometry

Abstract

Abstract A method is presented for the determination of the relatively new anticoccidial drug diclazuril in avian feed and premixes. The drug was extracted from feed with acidified methanol-water, and the extracts were cleaned up by simple liquid-liquid extraction. These were then derivatized with ethereal diazomethane, and the methyl derivatives were analyzed by gas chromatography/mass spectrometry on a bench-top instrument An internal standard was used to enhance the reproducibility and ruggedness 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%, respectively. 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 finished feed.