Free radical formation from sonolysis of water in the presence of different gases

Masahiro Kohno, Takayuki Mokudai, Toshihiko Ozawa, Yoshimi Niwano

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


In the present study by applying electron spin resoance-spin trapping method, when a high frequency (1650 kHz) ultrasound was irradiated to water dissolved with different gas molecules (O 2, N 2, Ar, Ne, He, and H 2) at 25°C of water bulk temperature, free radical generation pattern differed dependently on the dissolved gas molecules. Only ·OH was detected in the O 2-dissolved water sample, and the amount of the radical was much greater than that determined in any of other gas-dissolved water samples. One of the possible reasons to explain why the ·H radical was not detected in the O 2-dissolved water is that the ·H reacts with O 2 to form ·OOH. However, no electron spin resonance signals related to the adduct of not only 5,5-dimethyl-1-pyrroline-N-oxide but 5-(2,2-Dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide and ·OOH were observed. In the H 2-dissolved water, only ·H was detected, suggesting that H 2 reduces or neutralizes ·OH. In the N 2-disolved water, both ·OH and ·H were detected at comparable level. In the water samples dissolved with rare gases (Ar, Ne, and He), the amount of ·H was almost double as compared with that of ·OH, and both ·OH and ·H yields increased in the order Ar > Ne > He.

Original languageEnglish
Pages (from-to)96-101
Number of pages6
JournalJournal of Clinical Biochemistry and Nutrition
Issue number2
Publication statusPublished - 2011 Sep


  • Electron spin resonance
  • Radical formation
  • Water sonolysis

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Clinical Biochemistry


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