没食子酸清除DPPH自由基的微量电化学滴定  

Micro-Electrochemical Titration Analysis of the Scavenging Effect of Gallic Acid on DPPH Free Radicals

作　　者：李晓芬[1] 王炯[1] 李桥丽[1] 高云涛[1] 张公信[1] 周学进[1] 

机构地区：[1]云南民族大学民族药资源化学国家民委-教育部重点实验室,云南昆明650500

出　　处：《云南民族大学学报（自然科学版）》2012年第4期243-248,共6页Journal of Yunnan Minzu University:Natural Sciences Edition

基　　金：云南省创新团队项目(2011HC008);民族药资源化学国家民委-教育部重点实验室开放基金(MJY07010)

摘　　要：电化学研究表明,没食子酸在石墨电极上有一不可逆的氧化峰,峰电位为Epa=0.48 V,且在0.38 V(vs.SCE)处有一灵敏的差分脉冲伏安氧化峰,其峰电流与浓度具有良好的线性关系,ipa=2.408c+3.028,r=0.999 6.建立了没食子酸清除DPPH自由基的新型微量电化学滴定法,研究了没食子酸和DPPH自由基反应的化学计量关系,测得没食子酸和DPPH自由基反应的化学计量比为1∶3,该结果与光谱分析法相符,并对没食子酸清除DPPH自由基的电化学氧化机理进行了探讨.The electrochemical results indicated that gallic acid presented typical irreversible oxidation processes, and an irreversible oxidation peak was observed with the peak potentials of 0.48V （vs. SCE） on the graphite elec- trode. A sensitive differential pulse vohammetry anodic peak at Epa = 0.38V （vs. SCE） was also detected with a good linear relationship between the peak current and the concentration ： ipa = 2. 408 c ＋ 3. 028, r = 0.999 6. A novel micro - electrochemical titration method for evaluating the scavenging effect of gallic acid on DPPH free radi- cals was proposed, the stoichiometric relationship of gallic and DPPH was determined with a stoichiometric propor- tion of 1：3 （gallic to DPPH）, which was coincident with the results of spectrophotometry. Electrochemical oxida- tion mechanism of the scavenging effect of gallic acid on DPPH free radicals was also investigated.

关 键 词：没食子酸 DPPH自由基 电化学滴定 化学计量 电化学氧化机理 

分 类 号：O657.7[理学—分析化学] R284.1[理学—化学]