title: DMPO-OH radical formation from 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in hot water.
abstract: When an aqueous solution of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was heated at 70 degrees C for 30 min, formation of DMPO-OH was observed by ESR. This DMPO-OH radical formation was suppressed under an argon atmosphere. When water was replaced with ultra-pure water for ICP-MS experiments, DMPO-OH radical formation was also diminished. Under an argon atmosphere in ultra-pure water, the intensity of the DMPO-OH signal decreased to about 1/20 of that observed under aerobic conditions with regular purified water. The addition of hydroxyl radical scavengers such as mannitol did not affect the formation of DMPO-OH, but the signal turned faint in the presence of EDTA. We suggest that DMPO reacted with dissolved oxygen to form DMPO-OH.
authors.affiliation: Kyoritsu University of Pharmacy, Shibakoen, Minato, Tokyo, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Shoji
authors.forename: Linxiang
authors.initials: L
authors.lastname: Li
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Abe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ogata
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ishimoto
authors.forename: Ryoko
authors.initials: R
authors.lastname: Gonda
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Mashino
authors.forename: Masataka
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Michihisa
authors.initials: M
authors.lastname: Uemoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Miyata
mesh_terms: D001128:Argon / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry; D003497:Cyclic N-Oxides / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry*; D008353:Mannitol / Q000737:chemistry; D013058:Mass Spectrometry; D010100:Oxygen / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D016166:Free Radical Scavengers; D014867:Water; D017665:Hydroxyl Radical; D008353:Mannitol; D001128:Argon; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D010100:Oxygen