Ethopabate in Admixture Premixes and in Final Fodders by HPLC with Fluorescence Detection. Interlaboratory Comparative Test of the Method

Abstract

An HPLC method of determination of ethopabate for the purpose of rapid monitoring its contents in admixture premixes and in final fodders was developed. Ethopabate is extracted from a sample with methanol and after purification of the extract on basic aluminium oxide it is determined by HPLC on the C18 reverse phase with fluorescence detection. The values of the determination limit (15 µg/kg), repeatability (0.63 mg/kg) and the yield of the method (100.2 ± 3.6 %) were determined in the ethopabate concentration range 1.3-10.7 mg/kg. The repeatability value was determined with samples of real fodders. From the interlaboratory circular tests of the determination, the repeatability index was calculated, amounting to 5-6 % at 2-2400 mg/kg. The reproducibility index ranges between 13 and 18 %.