【Abstract】 The synthesis of a novel α phosphorus containing spin trap, DEPDMPO(5 diethoxy Phosphoryl 2, 5 dimethyl 1 pyrroline \%N\% oxide) and the evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability to trap an active superoxide anion radical generated in the photo system Ⅱ(PSII) and the stability of their spin adduct of DEPDMPO as well as three previously reported traps DMPO, DEPMPO and M 3PO were comparatively analyzed according to their chemical structures. In addition, the effects of 2 methyl and \%α\% phosphoryl substituted analogues of DMPO on the stabilities of the corresponding spin adduts were systematically illustrated更多还原