title: Identification of a radical formed in the reaction mixture of rat brain homogenate with a ferrous ion/ascorbic acid system using HPLC-EPR and HPLC-EPR-MS.
abstract: Identification of a free radical is performed for the reaction mixture of rat brain homogenate with a ferrous ion/ascorbic acid system using EPR, high performance liquid chromatography-electron paramagnetic resonance spectrometry (HPLC-EPR) and high performance liquid chromatography-electron paramagnetic resonance-mass spectrometry (HPLC-EPR-MS). EPR measurements of the reaction mixtures showed prominent signals with hyperfine coupling constants (alpha(N) = 1.58 mT and alpha(H)beta = 0.26 mT). No EPR spectrum was detectable without rat brain homogenate, suggesting that the radical is derived from rat brain homogenate. An HPLC-EPR analysis of the reaction mixture showed a peak with retention time of 33.7 min. An HPLC-EPR-MS analysis of the peak gave two ions at m/z 224 and 137, suggesting that alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN)/ethyl radical adduct forms in the reaction mixture.
authors.affiliation: Department of Pharmacology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Kumamoto
authors.forename: Tomihiro
authors.initials: T
authors.lastname: Hirai
authors.forename: Shiroh
authors.initials: S
authors.lastname: Kishioka
authors.forename: Hideo
authors.initials: H
authors.lastname: Iwahashi
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000737:chemistry* / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004578:Electron Spin Resonance Spectroscopy; D005296:Ferrous Compounds / Q000737:chemistry* / Q000378:metabolism; D005609:Free Radicals / Q000032:analysis*; D008297:Male; D013058:Mass Spectrometry; D051381:Rats; D017208:Rats, Wistar; D013113:Spin Labels; D019097:Spin Trapping
chemical_list: D005296:Ferrous Compounds; D005609:Free Radicals; D013113:Spin Labels; D001205:Ascorbic Acid