Effects of Cu²⁺ and Detergents on the Autoxidation of Hydroxylamine Involving Superoxide Anion Radicals

Abstract

The reduction rate of nitro-blue tetrazolium by Superoxide anion radicals during the autoxidation of hydroxylamine (20 μm) was inhibited by 67% in the presence of 5 μm Cu²⁺. However, upon the addition of a cationic micelle of hexadecyltrimethylammonium bromide or a nonionic micelle of polyoxyethylene dodecyl ether, the reduction rate markedly increased with an increase of the concentration of Cu²⁺. The coexistence of 10 μm Cu²⁺ and 5 mm cationic or nonionic micelle accelerated this reaction about 50- or 75-fold, respectively, although the absence of Cu²⁺ accelerated the reaction rate only about 8,0- or 6.0-fold, respectively. On the other hand, the generation rate of nitrite during the autoxidation of hydroxylamine was increased by the addition of Cu²⁺ and decreased by the addition of the micelles. The coexistence effect of Cu²⁺ and micelles was not observed in the case of nitrite formation reaction. The microenvironmental effects on these reactions were discussed.