The use of a nitroxide probe in DMSO to capture free radicals in particulate pollution

A profluorescent nitroxide was used to evaluate the oxidative potential of pollution derived from a compression ignition engine fuelled with biodiesel. The reaction products responsible for the observed fluorescence increase when a DMSO solution of nitroxide was exposed to biodiesel exhaust were determined by using HPLC/MS. The main fluorescent species was identified as a methanesulfonamide adduct arising from the reaction of the nitroxide with DMSO-derived sulfoxyl radicals. The oxidative potential of particulate pollution derived from a biodiesel engine exhaust stream was evaluated by using a profluorescent nitroxide. A methanesulfonamide adduct arising from the reaction of the nitroxide with DMSO-derived sulfoxyl radicals was identified as the main fluorescent product. © 2012 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.