The optimisation of a rapid method for the determination of lasalocid in poultry feed using supercritical fluid extraction and high performance liquid chromatography

A simple and rapid method, using supercritical fluid extraction with off-line high-performance liquid chromatography for the isolation and determination of lasalocid in poultry feed is described. Lasalocid is widely used as a coccidiocidal drug in poultry and for increased feed efficiency as well as for weight gain in ruminant animals, namely cattle and sheep. Results show good repeatability with a minimum quantification level of 0.5 μg g−1 and mean ‘spiked’ recovery of 100% using poultry feed (n=32) spiked with lasalocid in the range of 0.5–125 μg g−1. Carbon dioxide used as a supercritical fluid is proposed as an alternative isolation method to the current solvent extractions, which generally require lengthy clean up procedures prior to the assay.