USE OF A PHOSPHORYLATED SPIN TRAP TO DISCRIMINATE BETWEEN THE HYDROXYL RADICAL AND OTHER OXIDIZING SPECIES

The spin-trap 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMP O) is shown to provide a simple method to distinguish free-radical rea ctions which lead to the production of (OH)-O-. from those which proce ed via one-electron transfer followed by hydration or nucleophilic sub stitution of another adduct, In the first case, only an (OH)-O-. adduc t is detected; in the latter, signals from the hydroxyl adduct (labell ed with O-17 when H-2 O-17 is-employed) are accompanied by a second si gnal believed:to result via internal trapping of a radical formed from an intermediate radical cation, This provides a potentially useful me chanistic probe, for example for use in biochemical systems.