Fenton反应产生的羟自由基及其清除的电化学方法测定

Determination of Hydroxy Radical and Its Scavenging Rate by Electrochemical Method

建立了一种新的测定羟自由基的电化学方法 ,Fenton反应产生的羟自由基氧化二甲亚砜 (DMSO)生成的甲醛与乙酰丙酮、氨发生Hantzsch反应 ,产物3,5_二乙酰基_1,4_二氢吡啶在 -1.20V(vsSCE)处有一灵敏的二阶导数极谱波 ,通过峰电流变化可间接测定羟自由基 ;拟定的方法测定了数种清除剂与羟自由基反应的反应速率常量和清除羟自由基的IC50;该法简便可靠 。

An electrochemical method for the determination of hydroxy radical was proposed. Hydroxy radicals, generated by Fenton reaction, attacks dimethyl sulfoxide to form formaldehyde. There occurs Hantzsch reaction of the formed formaldehyde with ammonia and 2,4-pentanedione and forms 3,5-diacetyl-1,4-dihydropyridine at pH of ≈6.2. The product shows a second-order derivative reduction wave with the peak potential of -1.20 V(vs SCE) in oscillopolarogram. The quantitative analysis of hydroxy radical can be done through the determination of the peak current. The IC50 and rate constant of reaction for several scavengers were detected by proposed method with satisfatory results. This method is simple and can be employed for researching hydroxy radical scavengers.