Determination of XXXX in feedstuffs with liquid chromatographic preparatory column cleanup and quantitative analysis.

@entity4315 @entity27411 @entity1042 @entity3636 @entity2397 @entity5383
@entity27411 (MGA) is determined by liquid chromatography using a fraction from preparatory LC as a means of sample cleanup for feedstuffs, both dry and liquid. Dry ground feed is Soxhlet extracted with @entity4315 and passed through a 2% deactivated @entity5383 column for initial cleanup. The eluate is evaporated, redissolved in @entity1042 , filtered, and injected onto a preparatory LC column. The fraction containing MGA is separated from the remaining matrix, evaporated to dryness, dissolved in @entity1042 , and quantitated by LC analysis. Liquid supplements are extracted in @entity1042 , and the extract is evaporated to near dryness. The residue is diluted with water, extracted with @entity3636 , passed through @entity2397 , and evaporated to dryness. The remaining sample is dissolved in @entity1042 prior to preparative LC and quantitative LC. Recoveries for 2 laboratory-fortified commercial feeds, one dry and one liquid, containing 0.39 and 0.40 mg/lb, were 98.3% +/- 4.4 and 95.8% +/- 4.3, respectively. Results compare favorably with existing methods. Up to a 4-fold time savings was realized by this method without automation.
