摘要
在pH 7.0 Britton-Robinson缓冲溶液中,米非司酮(Mifepristone,RU486)在汞电极上有2个不可逆的线性扫描还原峰,峰电位分别为-1.23V和-1.68V(vs.SCE)。本文探讨了第一峰的电化学行为。该峰具有明显的吸附性,吸附粒子为RU486分子,测得饱和吸附量为1 .09 X 10-10 mol/L,吸附系数p= 1 .10 X 105 ,吸引因素y= 1 .67,吸附自由能- 28.76 kJ/mol,电子转移数 n= 2,转移系数 a= 0.58,表面电极反应的速率常数 ks = 0.16 S-1,探讨了 RU486在汞电极上的还原机理。
In a supporting electrolyte containing B-R buffer solution at pH 7.0, two irre- versible reduction-peaks of Mifepristone(RU486) was found by linear-sweep voltammetry at Hg electrode, with the potentials Epc1=-1.23 V and Epc2=-1.68 V(vs. Ag/AgCl), re- spectively. This paper studied the electrochemistry of the first one emphatically. The peak shows adsorptive characteristics. The adsorbed species is most probably neutral molecule of RU486. The saturated adsorption amount of RU486 at Hg electrode is 1.09 X 10-10 mol/cm2. The adsorption coefficient β is 1. 10 X 105, the attraction factor γ is 1. 67 and the adsorption free energy is -28. 76 kJ/mol. The number of electrons transferred per RU486 molecule n is 2 and the transfer coefficient a of the irreversible adsorptive system of RU486 is 0. 58. The rate constant of surface electrode reaction k3 is 0. 16 s-1. The mechanism of electrochemical reduction of RU486 at Hg electrode is explored.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1997年第11期1278-1281,共4页
Chinese Journal of Analytical Chemistry
基金
国家自然科学基金
关键词
米非司酮
电化学性质
吸附伏安法
Mifepristone, electrochemical characterstics. adsorptive stripping voltammetry