Exchange of 18O in the reaction of peroxynitrite with CO2
- Resource Type
- Article
- Authors
- Tu, Chingkuang; Quint, Patrick; Silverman, David N.
- Source
- Free Radical Biology & Medicine. Jan2005, Vol. 38 Issue 1, p93-97. 5p.
- Subject
- *MASS spectrometry
*CARBON compounds
*FREE radical reactions
*SPECTRUM analysis
*HYDRATION
- Language
- ISSN
- 0891-5849
Abstract: We have observed an exchange of 18O in the reactions of CO2 with peroxynitrite using membrane-inlet mass spectrometry and HPLC negative electrospray ionization mass spectrometry. The exchange appeared on addition of peroxynitrite to a solution containing 18O-labeled CO2 in equilibrium with bicarbonate. It was observed as a temporarily enhanced rate of depletion of 18O from CO2, a rate that was greater than the rate of 18O depletion caused by the hydration/dehydration cycle of CO2. In addition, we detected the appearance of mass peaks attributed to 18O in product NO3–.As a further measure of the 18O exchange, there was a redistribution of 18O such that the ratio of doubly to singly labeled CO2 could not be described by the binomial expansion. This is not due to the hydration/dehydration cycle of CO2 but most likely to recycling of CO2 in the reaction with peroxynitrite. This 18O exchange associated with the reactions of CO2 and peroxynitrite may open a new methodology for studying this significant process. [Copyright &y& Elsevier]