title: Simultaneous determination of tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry.
abstract: Simultaneous quantification method of three major metabolites of cortisone and cortisol, tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was investigated in a positive mode using a recently developed picolinyl derivatization. Conversion of each steroid into the corresponding picolinyl derivatives (1b, 2b or 3b) was performed by mixed anhydride method using picolinic acids and 2-methyl-6-nitrobenzoic anhydride. Derivatization proceeded smoothly to afford the corresponding 3, 21-dipicolinyl derivatives. Positive ion-ESI mass spectra of the picolinyl derivatives were dominated by an appearance of [M+H](+) as base peaks in all cases. The picolinyl derivatives provided 15 to 80-fold higher ESI response in the LC-ESI-MS/MS (selected reaction monitoring: SRM) when compared to those of underivatized molecules in a positive LC-ESI mode. The use of the picolinyl ester, solid-phase extraction, and deuterium labeled internal standards enabled the concentrations of these metabolites in human urine to be determined simultaneously by LC-ESI-MS/MS (SRM) with a small sample volume of less than 1microl urine.
authors.affiliation: Faculty of Pharmaceutical Science, Tohoku Pharmaceutical University, Aoba-ku, Sendai, Miyagi 981-8558, Japan. kyama@tohoku-pharm.ac.jp
authors.forename: Kouwa
authors.initials: K
authors.lastname: Yamashita
authors.forename: Risa
authors.initials: R
authors.lastname: Nakagawa
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Okuyama
authors.forename: Seijiro
authors.initials: S
authors.lastname: Honma
authors.forename: Madoka
authors.initials: M
authors.lastname: Takahashi
authors.forename: Mitsuteru
authors.initials: M
authors.lastname: Numazawa
mesh_terms: D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry; D013760:Tetrahydrocortisol / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000652:urine; D013761:Tetrahydrocortisone / Q000737:chemistry / Q000652:urine*
chemical_list: C006461:allotetrahydrocortisol; D013761:Tetrahydrocortisone; D013760:Tetrahydrocortisol