Abstract
A method for the determination of sulfaquinoxaline (SQ) in feed by HPLC has been developed. The ion pair chromatography method was suitable for the separarion of SQ from the ingredients. SQ was extracted from feed with 100 ml of dimethylformamide (DMF) and the extract was placed in a boiling water bath, with intermittent stirring, for 30 min. The supernatant was applied to an alumina column (E. Merck 1076, 10 g), then washed with ether, chloroform-methanol (3+1) and eluted with methanol. The effluent was injected onto a HPLC column. The recovery of SQ added to feeds at 60 μg/g of feed was 97.3%, and the detection limit was 0.5 μg/g. The recovery of SQ from feeds, as reported by 6 collaborators, was 101.9%, with a relative standard deviation of 4.1%. The proposed method can be applied to the determination of SQ in pellet feed and is recommended as an official method of feed analysis in Japan.
