超氧自由基电化学发生体系的研究

超氧自由基是人体内氧代谢的重要产物 1 ] .迄今为止 ,超氧自由基的研究方法有电子自旋共振法、光度法和电化学法等 2～ 5] .其中 ,通过电化学还原氧产生超氧自由基是一种简便快捷的方法 6,7] .本文使用长链表面活性剂 DSAB作为疏水分子 ,比较了强碱性介质中氧在汞电极和 4种非汞电极上的电化学还原行为 ,建立了超氧自由基在非汞电极 (铂电极 )上电化学发生新体系 .通过石英晶体微天平和计时电量法进一步证实了超氧自由基的产生 ,并用循环伏安法比较了抗坏血酸和半胱氨酸两种抗氧化剂对超氧自由基的清除能力 .1　实验部分1.1　试剂与仪…

Studies on Electrochemical Generation System of Superoxide Free Radical

A mercury-free solid electrode system for the electrochemical generation of O ·- 2 was described. The effects of pH, the amount of the surfactant and electrode materials on the reduction of O2 were investigated. The electrogeneration of O ·- 2 was only obtained at the Pt electrode in this medium system. The different electrochemical behaviour of O2 at Pt electrode and Au electrode were explained in terms of the different adsorptions of DSAB, which was confirmed by quartz crystal microbalance(QCM). The frequency responses for the reduction of O2 at Pt electrode and Au electrodes were compared by electrochemical quartz crystal microbalance(EQCM), suggesting that the electrogenerated O ·- 2 was adsorbed on the surface of the Pt electrode. The one-electron reduction of oxygen in this system was also confirmed by using chronocoulometry. The scavenging activities of two kinds of antioxidants(ascorbic acid and cysteine) were examined and compared.