A method for the separation of residues of nine compounds in cattle liver related to treatment with oxfendazole

Abstract

A method for the determination of nine compounds closely related to oxfendazole has been developed for the monitoring of residues in food. The method is based on a multi-residue procedure for basic drug residues and used strong cation exchange solid phase extraction for sample clean-up. These nine compounds include fenbendazole, which is itself a licensed veterinary product. The pro-drug febantel converts quickly to fenbendazole or oxfendazole soon after administration. The method is therefore suitable for monitoring residues following the use of any of these compounds. Some of these analytes have been shown to be present as residues following the treatment of farm animals with oxfendazole. Average recoveries for the nine compounds from tissue fortified with 100 µg kg^–1 were between 34% and 96% with relative standard deviations between 3% and 22%.