Abstract
Abstract Activation of hydrogen peroxide by Cu(II) complexes of native amino acids (L) has been studied by measuring the initial oxidation rate of quinaldine blue (QB) in aqueous phosphate media at 25°C. Hydrogen peroxide is an effective oxidant that can generate many kinds of reactive oxygen species to oxidize organic compounds. However, the mechanistic pathway that includes either hydroxyl radical or Cu(I)OOH as the major reactive species is unclear. The formation rate of OH can be observed by adding p-Nitrosodimethylaniline(PNDA). Methional is a copper- hydroperoxo complex (Cu(I)OOH) scavenger that can inhibit the oxidation of organic compounds. From the experimental results, the major reactive species is identified that is Cu(I)OOH. Based on the formation of Cu(I) and OH by effect of methional, a possible mechanism is proposed. Moreover, aldyhydes and organic acids in Cu(II)- amino acid complexes system always inhibit the degradation of QB. Keywords : Hydrogen peroxide; Copper complex; Amino acid; Quinaldine blue; Methional; PNDA