Spin trapping magnetic resonance determination of atmospheric species

Spin trapping is a versatile technique for the detection of transient radicals with applications in chemistry and biochemistry. The technique detects short-lived reactive radicals by their addition reaction with a nitrone or nitroso compound which produces aminoxyl radicals that are relatively more stable for detection than the free radicals. This research was aimed at spin trapping gaseous peroxy radicals using solid and solution phase spin traps; and Electron Paramagnetic Resonance (EPR) Spectroscopy to detect the spin adducts formed. Known concentrations of PBN, nitrosobenzene and nitrosobutane were used as spin traps for Di-tert-butylperoxide and EPR spectroscopy was used for detection of the spin adducts which were used as reference and optimization of the spectrometer used for this research and a medium of comparison and quantification for gaseous peroxy radicals used for this research. The results were promising as Nitrosobenzene demonstrated its ability to spin trap gaseous peroxy radicals both in its solid and solution phases respectively by giving rise to series of spectra that suggest that spin trapping has occurred. PBN on the other hand showed its capability only in the solid phase while its solution seems not to spin trap gaseous peroxy radicals in this research probably due to its high reactivity when exposed to air, moisture and light. The research found out that 1g each of PBN and Nitrosobenzene respectively were probably capable of spin trapping reasonable amounts of gaseous peroxy radicals while 1ml of 0.1M Nitrosobenzene will likely spin trap more radicals than the solid phase spin traps. This result suggests that solution phase spin traps were probably more effective in spin trapping gaseous peroxy radicals than solid phase spin traps.