Quantification of Singlet Oxygen Production in the Reaction of Superoxide with Hydrogen Peroxide Using a Selective Chemiluminescent Probe

Laura A. MacManus-Spencer and Kristopher McNeill*
Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
J. Am. Chem. Soc., 2005, 127 (25), pp 8954–8955
DOI: 10.1021/ja052045b
Publication Date (Web): June 4, 2005
Copyright © 2005 American Chemical Society
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, mcneill@chem.umn.edu

Abstract

Abstract Image

A sensitive chemiluminescent probe that selectively reacts with singlet oxygen in the presence of superoxide and hydrogen peroxide has been used to quantify the production of singlet oxygen in the reaction of superoxide with hydrogen peroxide. The yield of singlet oxygen from this reaction was found to be low (0.2% relative to the initial superoxide concentration). No evidence for the formation of hydroxyl radical was observed in this reaction, ruling out the Haber−Weiss mechanism as a major singlet oxygen formation pathway. No singlet oxygen production was observed in the reaction of superoxide with 2-nitrobenzoic acid, which has a pKa similar to that of hydrogen peroxide, rendering the protonation of superoxide, followed by its disproportionation, an unlikely explanation for the formation of singlet oxygen in this system. The low yields of singlet oxygen and hydroxyl radical suggest that their formation in this reaction should be relatively unimportant in biological systems.

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History

  • Published In Issue June 29, 2005
  • Received March 31, 2005

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