Detection and characterization of hydroxyl radical adducts by mass spectrometry

The study of the influence of free radicals in the biological process depen ds primarily on the capacity to detect these reactive species. In this work we have studied the application of mass spectrometry to the identification of hydroxyl radical species. The detection and identification by collision al activation mass-analyzed ion kinetic energy spectrometry (CA-MIKES) of a spin adduct of DMPO with the hydroxyl radical [(DMPO + O) + H](+) (m/z 130 ) has demonstrated that mass spectrometry can be a powerful tool in the det ection and identification of spin adducts of DMPO with hydroxyl radical spe cies. We were also able to detect the capture of secondary free radicals us ing ethanol by detecting and identifying the corresponding adduct [(DMPO ethanol) + H]+. Other spin adducts have also been detected and identified. We consider that the use of mass spectrometry is a relevant technique for t he detection of free hydroxyl radicals, especially in complex mixtures, sin ce mass spectrometry is able to discriminate these adducts in such situatio ns. Moreover, using this approach, it was possible to identify new spin add ucts. (C) 2001 American Society for Mass Spectrometry.