摘要
在NH_3-NH_4Cl底液中,噻利洛尔(Celiprolol,简称CEL)在汞电极上有一线性扫描还原峰,峰电位E_(pc)=-1.31V(vs.Ag/AgCl),该峰具有明显的吸附性.当CEL浓度较小时,扫速较快,搅拌富集时间较长时,电极反应完全为吸附态的CEL的还原所控制,吸附粒子为CEL中性分子,测得CEL在汞电极上的饱和吸附量为1.03 ×10^(-10) mol/L,每个CEL分子所占电极面积为1.57nm^2,CEL在悬汞电极上的吸附符合Langmuir等温式.测得吸附系数β=1.08×10~6,电子转移数(n)为2,不可逆吸附的电子转移系数(α)为0.74,表面电极反应的速率常数k_(?)=0.40/s.探讨了CEL在汞电极上的还原机理,并建立了吸附伏安法测定CEL的最佳条件,检出限为1.0×10^(-9)mol/L.
In a supporting electrolyte containing NH3·H2O-NH4Cl, a reduction peak of celiprolol ( CEL)was observed by linear-sweep voltammetry at Hg electrode. The peak shows a potential of -1.31 V(vs. Ag/AgCl) and adsorptive characteristics. When the concentration of CEL is sufficiently low, the sweep rate is sufficiently rapid, and the accumulation time is sufficiently long, the peak current is totally contributed by the reduction of adsorbed CEL. The adsorbed species is most probably neutral molecule ofCEL. The saturated adsorption amount of CEL at Hg electrode is 1.03×10-10 mol/cm2 and every CELmolecule occupies 1.57 nm2. On the surface of hanging mercury drop electrode, the adsorption of CELobeys Langmuir adsorption isotherm. The adsorption coefficient (β) is 1. 08×106. The number ofelectrons transferred per CEL molecule ( n ) is 2 and the transfer coefficient (α) of the irreversiblesdsorptive system of CEL is 0.74. The rate constant of surface electrode reaction ( ks) is 0.40 s-1. Themechanism of electrochemical reduction of CEL, at Hg electrode is explored. The detection limit of theadsorptive stripping voltammetry of CET, is 1.0×10-9mol/L under optimized condition.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1999年第10期1136-1140,共5页
Chinese Journal of Analytical Chemistry
关键词
噻利洛尔
吸附溶出伏安法
电化学
测定
双胺心安
Celipiolol, adsorptive stripping voltammetry, electrochemical characteristics
