Determination of pyrimethamine, ethopabate and sulphaquinoxaline in poultry feeding stuffs by high-performance liquid chromatography using a weak cation-exchange column packing

Abstract

A method based on high-performance liquid chromatography, using a weak cation-exchange column packing, is described for the simultaneous determination of pyrimethamine, ethopabate and sulphaquinoxaline in poultry feeding stuffs. The method is applicable to mash and pelleted feeds containing at least 1 mg kg^–1 of pyrimethamine and ethopabate and to mash feeds containing at least 5 mg kg^–1 of sulphaquinoxaline. A comparison is made between this and other methods of analysis of these prophylactics and, with the exception of sulphaquinoxaline in pelleted feeds, good agreement is obtained. An alternative procedure is described for the determination of sulphaquinoxaline in pelleted feeds.