摘要 本研究利用Cu(II)與自然胺基酸形成的銅錯合物,於25℃的磷酸鹽溶液中活化過氧化氫,並偵測反應中2-甲喹咻藍(QB)的初始氧化速率來探討銅錯合物活化過氧化氫效率。過氧化氫是種很強的氧化劑,在反應中能產生許多種活性氧化物種來分解QB,然而最主要的活性氧化物種為何,仍不得而知。故本研究藉由使用亞硝基二甲基苯胺(p-Nitrosodimethylaniline, PNDA)來觀察系統中產生OH●的多寡,以及使用3-甲硫基丙醛(methional)來觀察其對系統中QB分解反應的影響,methional是Cu(I)OOH●的清除劑,對系統中QB的分解速率有很明顯的抑制效果,故由實驗結果能確定最主要的活化氧化物種為Cu(I)OOH●,最後藉由methional對於一價銅與OH●生成的影響,推導出過氧化氫活化的反應機制。此外,系統中若有其他有機物質,例如:醛、有機酸時,則會對系統的QB分解速率有抑制的影響。 關鍵字:過氧化氫;銅錯合物;胺基酸;2-甲喹咻藍;3-甲硫基丙醛;亞硝基二甲基苯
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