DEPMPO is a phosphorylated derivative of the widely used DMPO spin trap. It has been reported to produce spin adducts with increased stability particularly for the adduct of superoxide. [1] [2] [3] DEPMPO displays a detectable spin adduct signal at a concentration as low as 1 mM, as compared to 5 mM for DMPO.[3] A significant advantage of using DEPMPO in trapping superoxide radical is that the decomposition of DEPMPO/O2o- does not produce the OHo adduct, which can be a drawback when using DMPO. [2][3]

Reference:
[1]. Khan, N., Wilmont, C.M., Rosen, G.M., et al. Spin traps: In vitro toxicity and stability of radical adducts. Free Radical Biology & Medicine 34(11), 1473-1481 (2003).
[2]. Anzai, K., Aikawa, T., Furukawa, Y., et al. ESR measurement of rapid penetration of DMPO and DEPMPO spin traps through lipid bilayer membranes. Archives of Biochemistry and Biophysics 415, 251-256 (2003).
[3]. Liu, K.J., Miyake, M., Panz, T., et al. Evaluation of DEPMPO as a spin trapping agent in biological systems. Free Radical Biology & Medicine 26, 714-721 (1999).