title: Simultaneous quantitation of testosterone, estradiol, ethinyl estradiol, and 11-ketotestosterone in fathead minnow fish plasma by liquid chromatography/positive atmospheric pressure photoionization tandem mass spectrometry.
abstract: In the present work, for the first time, a rapid and sensitive liquid chromatography/positive atmospheric pressure photoionization tandem mass spectrometry (LC/APPI-MS/MS) method has been developed and validated for the simultaneous quantitation of testosterone, estradiol, ethinyl estradiol, and 11-ketotestosterone in fathead minnow fish plasma using no more than 10 microL of plasma. Compounds present in plasma were directly derivatized with dansyl chloride and 25 microL of the derivatized mixture was injected into the LC/APPI-MS/MS system. The gradient chromatographic elution was achieved on an Agilent Zorbax SB-C18 analytical column (2.1 mm x 50 mm, 1.8 microm particle size) with mobile phases consisting of acetonitrile, water and acetic acid. The flow rate was 0.5 to 0.7 mL/min and the total run time was 11.5 min. The lower limits of quantitation for testosterone, estradiol, ethinyl estradiol, and 11-ketotestosterone and were 1, 1, 1, and 2.5 ng/mL, respectively. Intra-batch precision was less than 19.4% and inter-batch precision was less than 11.7% for all four analytes. Accuracy was within 83.5-115.4% of nominal concentrations. This method is used for quantitation of sex steroid levels in fathead minnow tested in endocrine disruptor screening experiments.
authors.affiliation: Toxicology and Environmental Research & Consulting, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA. fzzhang@dow.com
authors.forename: Fagen
authors.initials: F
authors.lastname: Zhang
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bartels
authors.forename: David R
authors.initials: DR
authors.lastname: Geter
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Carr
authors.forename: Lynn E
authors.initials: LE
authors.lastname: McClymount
authors.forename: Troy A
authors.initials: TA
authors.lastname: Marino
authors.forename: Gary M
authors.initials: GM
authors.lastname: Klecka
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D003530:Cyprinidae / Q000097:blood*; D004958:Estradiol / Q000097:blood*; D004997:Ethinyl Estradiol / Q000097:blood*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013739:Testosterone / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D013739:Testosterone; D004997:Ethinyl Estradiol; D004958:Estradiol; C003600:11-ketotestosterone