DMPO-OH Radical Formation from 5,5-Dimethyl-1-pyrroline N-Oxide (DMPO) in Hot Water
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When an aqueous solution of 5,5-dimethyl-1-pyrroline <i>N</i>-oxide (DMPO) was heated at 70°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.
- Analytical Sciences
Analytical Sciences 23(2), 219-221, 2007-02-10
The Japan Society for Analytical Chemistry