Spin trapping of nitric oxide (NO.) as aminoxyl radicals by its reaction with two species of short-lived radicals derived from azo compounds such as 2,2'-azobisisobutyronitrile and some aliphatic alcohols.

Aminoxyl radicals of the type R1N(O.)R2 are formed in the photochemical reaction between nitric oxide (NO.) and carbon-centered radicals R1. and R2.. R1. was formed from azo compounds such as 2,2'-azobisisobutyronitrile (AIBN): R1. = NC-C(CH3)2, 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN): R1. = CH3-CH(CH3)-CH2-C(CN)CH3, or 4,4'-azobis(4-cyanovaleric acid) (ACVA): R1. = HOOC-(CH2)2-C(CN) CH3. R2. was derived from aliphatic substances such as methanol, ethanol, or 2-propanol by homolytic abstraction of a hydrogen atom brought about by R1. from the azo compounds.