title: Determination of ethoxyquin in feeds by liquid chromatography: collaborative study.
abstract: Ethoxyquin is a chemical antioxidant used in feeds, ingredients, fats, and oils. A liquid chromatographic (LC) method for determination of ethoxyquin was developed. The method involves acetonitrile extraction of the sample and isocratic C18 reversed-phase chromatography with ammonium acetate buffer-acetonitrile as mobile phase and fluorescence detection. A collaborative study of the determination of ethoxyquin in various meals and extruded pet foods was conducted by The Iams Company Research Laboratory. Eleven laboratories analyzed 16 samples (including 2 blind duplicates) consisting of 7 meat meals and 9 extruded pet foods. Sample means ranged from 0.25 to 289 ppm. Repeatability standard deviations ranged from 0.08 to 3.2 ppm, and repeatability relative standard deviations ranged from 4.5 to 32%. Reproducibility standard deviations ranged from 0.12 to 13 ppm, and reproducibility relative standard deviations ranged from 4.5 to 55%. The LC method for determination of ethoxyquin in feeds has been adopted first action by AOAC INTERNATIONAL.
authors.affiliation: Iams Company, Lewisburg, OH 45338, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Schreier
authors.forename: R J
authors.initials: RJ
authors.lastname: Greene
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002021:Buffers; D002853:Chromatography, Liquid / Q000379:methods / Q000592:standards / Q000662:veterinary*; D005015:Ethoxyquin / Q000032:analysis* / Q000378:metabolism; D005396:Fish Products / Q000032:analysis*; D017408:Guidelines as Topic; D008461:Meat Products / Q000032:analysis*; D011202:Poultry Products / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D000097:Acetonitriles; D002021:Buffers; D005015:Ethoxyquin; C032159:acetonitrile