title: Fusaric acid as a novel proton-affinitive derivatizing reagent for highly sensitive quantification of hydroxysteroids by LC-ESI-MS/MS.
abstract: A highly sensitive derivatization method for liquid chromatography (LC)-electrospray ionization (ESI) tandem mass spectrometry of dehydroepiandrosterone (DHEA), testosterone (T), pregnenolone (P5), and 17alpha-OH-pregnenolone (17-OHP5) was developed based on the use of fusaric acid as a reagent. DHEA, P5, and 17-OHP5 were rapidly and quantitatively converted to the 3-fusarate esters by treatment with fusaric acid and 2-methyl-6-nitrobenzoic anhydride. The positive ESI-mass spectra of the fusarate esters of each steroid were dominated by the appearance of [M + H](+) as base peaks. The fusarate derivatization of these steroids showed 17.6-fold (DHEA), 11.9-fold (P5), 3.3-fold (17-OHP5), and 1.8-fold (T) higher sensitivity to those of the corresponding picolinate derivatives in LC-selected reaction monitoring.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tohoku Pharmaceutical University, Sendai, Japan. kyama@tohokupharm.ac.jp
authors.forename: Kouwa
authors.initials: K
authors.lastname: Yamashita
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Sachiko
authors.initials: S
authors.lastname: Komatsu
authors.forename: Mitsuteru
authors.initials: M
authors.lastname: Numazawa
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D005669:Fusaric Acid / Q000737:chemistry*; D006914:Hydroxysteroids / Q000032:analysis* / Q000737:chemistry; D011522:Protons; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D006914:Hydroxysteroids; D011522:Protons; D005669:Fusaric Acid