Determination of sulphadimidine in animal feeds by high-performance liquid chromatography

Abstract

A method is described for the determination of sulphadimidine in feeds at the 100 mg kg^–1 level with recoveries of greater than 90%. The drug is extracted with aqueous acetonitrile solution and is then isolated from the co-extractives using a cartridge containing a cation-exchange sorbent. Sulphadimidine is eluted from the cartridge with an eluent of the same composition as that of the mobile phase used in the high-performance liquid chromatography (HPLC) stage. A portion of the eluate is injected on to a reversed-phase HPLC column and the amount of drug present is determined by measuring its UV absorbance at 272 nm. The proposed method is particularly suitable for the assay of the drug in feedstuffs that have been stored for up to 3 months.