title: Trace analysis of ethinyl estradiol in casein diet using gas chromatography with electron capture detection.
abstract: Ethinyl estradiol (EE2) is an extremely potent synthetic estrogen and a common component in oral contraceptives. The drug has a well-characterized pharmacological profile and is used as a positive control in toxicological investigations of compounds having estrogenic activity. An analytical method developed for the determination of low microg/kg levels of EE2 in a casein-based rodent diet is presented. A methanol extract of casein diet is purified for instrumental analysis by a 3-fold solid-phase extraction process. The sample extract is derivatized with pentafluoropropionic anhydride to the pentafluoropropionyl product and analyzed by capillary gas chromatography with electron-capture detection. Recoveries of EE2 from casein diet fortified at 5, 10, and 50 microg/kg average 88.8% and have a relative standard deviation (%) of 7.2. The method limit of detection in a casein-based diet is 1 microg/kg.
authors.affiliation: National Center for Toxicological Research, Food and Drug Administration, Division of Biochemical Toxicology, Jefferson, AR 72079, USA.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Evans
authors.forename: Larry G
authors.initials: LG
authors.lastname: Rushing
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Billedeau
authors.forename: Claude L
authors.initials: CL
authors.lastname: Holder
authors.forename: Paul H
authors.initials: PH
authors.lastname: Siitonen
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002364:Caseins; D002849:Chromatography, Gas / Q000379:methods*; D004997:Ethinyl Estradiol / Q000032:analysis*; D005527:Food, Fortified / Q000032:analysis; D052616:Solid Phase Extraction
chemical_list: D002364:Caseins; D004997:Ethinyl Estradiol