title: Quantification of corticosteroids in human plasma by liquid chromatography-thermospray mass spectrometry using stable isotope dilution.
abstract: Liquid chromatography-thermospray mass spectrometry (LC-TSP-MS) using isotope dilution was investigated for quantitative analysis of cortisol, cortisone, prednisolone and prednisone in human plasma. Complete separation attained by a LiChroCART Supersupher reversed-phase column and elution with 0.05 M ammonium formate-tetrahydrofuran-methanol (180:53:17, v/v/v) resulted in a significantly large isotope effect of the deuterium-labeled analogs on the HPLC behavior and caused difficulty in quantification. Reduction of the isotope effect on the retention times using 0.05 M ammonium formate-acetonitrile (65:35, v/v) permitted accurate quantification of cortisol and cortisone by the isotope dilution LC-TSP-MS, although separation between cortisol and prednisone was incomplete.
authors.affiliation: Department of Medicinal Chemistry and Clinical Pharmacy, Tokyo College of Pharmacy, Hachioji, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shibasaki
authors.forename: T
authors.initials: T
authors.lastname: Furuta
authors.forename: Y
authors.initials: Y
authors.lastname: Kasuya
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D003348:Cortisone / Q000097:blood; D003903:Deuterium; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007201:Indicator Dilution Techniques; D013058:Mass Spectrometry; D011239:Prednisolone / Q000097:blood; D011241:Prednisone / Q000097:blood
chemical_list: D000305:Adrenal Cortex Hormones; D011239:Prednisolone; D003903:Deuterium; D003348:Cortisone; D011241:Prednisone; D006854:Hydrocortisone