SPIN TRAPPING OF THE SUPEROXIDE RADICAL BY 4-(N-METHYLPYRIDINIUM) t-BUTYL NITRONE

— The synthesis of 4-(N-methylpyridinium) t-butyl nitrone (4-MePyBN) and its use as a spin trap for superoxide radicals produced in aqueous solutions is reported (aN= 13.78 G, aHs= 1.65 G, and g = 2.0091). The half-life of the spin adduct as a function of pH (83 s at pH 5.5, 78 s at pH 7.0, and 65 s at pH 8.0) the effects of iron salts, diethylenetriaminepentacetic acid (DETAPAC), and superoxide dismutase were examined, and comparisons made between 4-MePyBN and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin trapping agents for the superoxide radical.