The paper describes spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol, which takes place via radicals at ambient temperature. The primary product of the decomposition is short-living ketyl radicals of phenylglyoxalic acid, which are captured and stabilized by means of the spin trap of N-terc-butyl-α-phenylnitrone. The spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol served as the source of radicals for the determination of the antioxidative effect of known antioxidants: C-vitamin, E-vitamin, and selenomethionine. It was found that the above-mentioned antioxidants are effective scavengers of radicals of phenylglyoxalic acid. On the basis of these data, the method can be recommended for testing the antioxidative properties of other substances as potential antioxidants.

        Key words: C-vitamin – D,L-selenometionine – electron paramagnetic resonance – E-vitamin – spin traping – free radicals