Drugs in feeds. Determination of sulfaquinoxaline in feeds: collaborative study
Szalkowski, C.R.
Journal - Association of Official Analytical Chemists 56(3): 758-761
1973
ISSN/ISBN: 0004-5756 PMID: 4779915 Document Number: 61092
In the method developed, sulfaquinoxaline is extracted from the feed sample with dimethylformamide and separated from interfering substances by chromatography on alumina. The isolated sulfaquinoxaline is diazotized and coupled in the presence of zirconium. The color complex is then extracted with butanol and measured at 550 nm. Recoveries of sulfaquinoxaline from feeds reported by 13 collaborators ranged from 96 to 101%, with a coefficient of variation of 5%. This assay method is suitable for determining sulfaquinoxaline at all levels and has been adopted as official first action, to replace methods 38.139 and 38.140–38.141.