DETERMINATION OF ARDACIN IN PREMIX, SUPPLEMENT, AND ANIMAL FEED BY A RAPID AND SENSITIVE 2-PEAK LIQUID-CHROMATOGRAPHIC METHOD WITH CORRELATION TO A GRADIENT MULTIPEAK LIQUID-CHROMATOGRAPHIC METHOD

A rapid and sensitive 2-peak liquid chromatographic (LC) method is des cribed for extracting and quantitating ardacin in premix, supplement, and animal feed formulations. Ardacin is extracted from the formulatio ns and analyzed after dilution or cleanup by reversed-phase LC with UV detection at 220 nm. The method correlates well with a more informati on-rich gradient multipeak LC method. Recoveries for premix formulatio ns ranged from 96.8% (relative standard deviation [RSD], 0.8%) to 103. 7% (RSD, 1.3%) for laboratory samples spiked at levels ranging from 1. 6 to 39.6% ardacin. Recoveries for protein supplement mash formulation s ranged from 98.7% of claim (RSD, 4.1%) to 106.0% of claim (RSD, 7.7% ) at ardacin levels ranging from 37.5 to 600 mg/lb. Recoveries for cat tle feed ranged from 90.0% of claim (RSD, 11.9%) to 105.6% of claim (R SD, 2.7%) at ardacin levels ranging from 4 to 30 g/ton.