DETERMINATION OF ARDACIN IN VARIOUS SILAGE FEED DIETS BY A RAPID LIQUID-CHROMATOGRAPHIC ASSAY

A method is presented for the detection and quantitation of Ardacin in silage feed diets by liquid chromatography, using a cyano column and an acetonitrile-methanol water mobile phase modified with trifluoroace tic acid. This method includes comprehensive procedures for extracting Ardacin from various silage feed formulations, cleaning up the extrac ted sample by using solid-phase extractions, and analyzing the eluted solid-phase extract with a suitable liquid chromatographic system. Ard acin was extracted from the silage feed formulations with 50% acetonit rile and 50% 0.1M KOH. The extract was cleaned up with a wide-pore but yl solid-phase extraction cartridge, The sample extract was chromatogr aphed and quantified at 220 nm, using an external method of calculatio n, Recoveries of the medicated silage feed formulation ranged from 72. 1 +/- 1.7% to 109.1 +/- 2.4%, depending on the sites and types of form ulation analyzed.