Quantitative analysis of a drug in an animal feed employing sample preparation by supercritical fluid extraction.

A pharmaceutical agent has been quantified in a rat feed matrix wherein sample preparation was achieved by supercritical fluid extraction. Spiking levels ranged from 0.0335% to 1.12%. Pure carbon dioxide, solid phase trapping on stainless steel with acetonitrile and liquid chromatographic assay yielded recoveries greater than 90% with relative standard deviations less than 5% in all cases except for the lowest spiking level. In this case recovery was 89.6% with an RSD of 9.6.