High pressure liquid chromatographic determination of bacitracin in premix feeds and finished feeds: collaborative study.

A liquid chromatographic technique for the determination of bacitracin in finished feeds and premix feeds consists of an isocratic reverse phase, ion-suppressed technique. The chromatography can be completed in less than 25 min. In a collaborative study involving 9 laboratories and 3 samples of bacitracin methylene disalicylic acid and 3 samples of bacitracin zinc premixes covering the range of 10-50 g/lb, the repeatability standard deviation was 0.55, and the reproducibility standard deviation was 1.35. The average recovery of the bacitracin was 102.0%. The method has been adopted official first action for bacitracin in premix feeds.