抗坏血酸与过氧化氢反应的自旋捕捉┐ESR研究  

The ESR Spin Trapping Studies of Reaction Between Ascorbic Acid with Hydrogen Peroxide

作　　者：白令君[1] 王建英[1] 

机构地区：[1]南开大学化学系

出　　处：《高等学校化学学报》1998年第6期890-894,共5页Chemical Journal of Chinese Universities

摘　　要：利用自旋捕捉－ＥＳＲ方法研究了分析纯抗坏血酸（Ａａ）与医用维生素Ｃ注射液（Ｖｃ）的自氧化和过氧化氢反应．在自氧化反应中只观察到去氢抗坏血酸负离子基Ａ－·，而与过氧化氢反应时除观察到Ａ－·外，还观测到另外数种自由基．经计算机拟合后得到这些自由基或其５，５－二甲基－１－吡咯啉－１－氧化物（ＤＭＰＯ）加合物的ＥＳＲ谱参数，在此基础上推测出该反应的机理．Using 5,5 dimethyl 1 pyrroline N oxide(DMPO) as a spin trapping reagent, the oxidation reaction of ascorbic acid was studied. The radical generated in autoxidation process was ascorbate radical anion(A -\5 ) only. In the presence of hydrogen peroxide, several radical intermediates were found and their structure were determined. The ESR parameters of A -\5 and DMPO/radical adducts were measured to be g =2.005 6 and α H=0.17 mT for A -\5 , g =2.005 9, α N=1.60 mT and α β H=2.28 mT for DMPO/1, g =2.005 9, α N=1.58 mT, α β H=2.13 mT and α γ H=0.17 mT for DMPO/2, g =2.005 9 and α N= α β H=1.49 mT for DMPO/\5OH , and g =2.005 9 and α N=1.50 mT for DMPO/3(or 4). The mechanisms for the oxidation reactions of ascorbic acid were proposed on the basis of those observation.

关 键 词：抗坏血酸 自旋捕捉 ESR 过氧化氢 羟基自由基 

分 类 号：Q564.02[生物学—生物化学] O613.3[理学—无机化学]