title: Hydroxyl radical generation by dissociation of water molecules during 1.65 MHz frequency ultrasound irradiation under aerobic conditions.
abstract: The dissociation of water molecules by ultrasound irradiation under aerobic conditions was demonstrated experimentally. To be able to detect the dissociation of water molecules, we performed the ultrasound irradiation of17O-labelled water (H217O) under aerobic conditions. The hydroxyl and hydrogen radicals generated during the ultrasound irradiation process were trapped with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and electron spin resonance (ESR) spectroscopy was performed on the DMPO spin adducts. In the ESR spectrum, a 15-line signal attributable to the trapping of the hydroxyl radicals containing17O (17OH radicals) by DMPO together with a 4-line signal attributable to the trapping of the hydroxyl radicals containing16O (16OH radicals) by DMPO were observed. The generation of17OH radicals indicated that H217O was dissociated by the sonolysis process under aerobic conditions. On the other hand, the ESR signal attributable to the trapping of hydrogen radicals by DMPO was not observed, suggesting that hydrogen radicals were not generated during the dissociation of water molecules.
authors.affiliation: School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Akimitsu
authors.initials: A
authors.lastname: Miyaji
authors.affiliation: School of Bioscience and Biotechnology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kohno
authors.affiliation: Showa Pharmaceutical University, 3-3165 Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan. Electronic address: tbaba@chemenv.titech.ac.jp.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Baba
mesh_terms: D000332:Aerobiosis; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D017665:Hydroxyl Radical / Q000737:chemistry*; D010103:Oxygen Isotopes / Q000032:analysis; D014465:Ultrasonics / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D010103:Oxygen Isotopes; D014867:Water; D017665:Hydroxyl Radical; C017245:5,5-dimethyl-1-pyrroline-1-oxide
keywords: (17)O-labelled water; High-frequency ultrasound; Hydroxyl radical; Oxidative stress; Water sonolysis