Spin trapping using 2,2-dimethyl-2H-imidazole-1-oxides.

The ability of novel cyclic nitrones, 4-substituted 2,2-dimethyl-2H-imidazole-1-oxides (IMO's) to trap a variety of short-lived free radicals has been investigated using ESR spectroscopy. IMO's scavenge oxygen-, carbon- and sulfur-derived free radicals to give persistent nitroxides. Compared to the spin trap 5,5-dimethyl-pyrroline-1-oxide, a higher lifetime of hydroxyl radical adducts and a higher selectivity related to the trapping of carbon-centered radicals was found.

[Macromolecular spin pH-probes on the basis of human serum albumin].

Human serum albumin has been chemically modified by two different spin pH-sensitive labels of the imidazoline series containing in their structure alkylating and carboxyl groups, respectively. The ESR spectra of spin-labeled proteins are sensitive to pH of the medium. The pK values of spin-labeled proteins measured by the ESR method are: pKI = 3.