Determination of efrotomycin in feeds by high-performance liquid chromatography

Abstract

A method for the determination of efrotomycin in feeds at concentrations of 2–16 p.p.m. is described. The drug is partitioned between dichloromethane and a mixed feed extraction solvent, and subsequently concentrated and freed from interferences on a commercially available amino-bonded-phase column. Final analysis is by HPLC with UV detection. The average recovery for a 4 p.p.m. spiked unmedicated feed was 101.6 ± 6.2%(n= 6); the recovery for pre-mix medicated samples containing 2–16 p.p.m. was 105 ± 9.9%(n= 36).