利凡诺的吸附溶出伏安法研究

Adsorptive Stripping Voltammetry of Rivanol

在NH_3-NH_4Cl底液中,利凡诺(RIL)在汞电极上有一线性扫描还原峰,E_(pc)=-1.42V(vs.饱和Ag/AgCl电极).该峰具有明显的吸附性.当RIL浓度较小,扫描速度较快,搅拌富集时间较长时,电极反应完全为吸附态的RIL的还原所控制.吸附粒子为RIL中的二氨基乙氧基吖啶中性分子.测得RIL在汞电极上的饱和吸附量为4.0×10^(-10)mol·cm^(-2),每个RIL分子所占电极面积为0.42nm^2,电子转移数n为2,不可逆吸附的转移系数α为0.71探讨了RIL在汞电极上还原的机理.并建立了吸附溶出伏安法测定RIL的最佳条件,最低检测限为1.0×10^(-9)mol·dm^(-3).

In a supporting electrolyte containing NH3-NH4Cl, a reduction peak of rivanol (RIL) was found by linear-sweep voltammetry at Hg electrode. The peak shows a potential of -1.42V (vs. Ag/AgCl) and adsorptive characteristics. When the concentration of RIL is sufficiently low, the sweep rate is sufficiently rapid land the accumulation time is sufficiently long, the peak current is totally contributed by the reduction of adsorbed RIL. The adsorbed species is most probably diaminoethoxyacridine neutral molecule of RIL. The saturated adsorption amount of RIL at Hg electrode is 4.0s×10-10mol·cm-2 and every RIL molecule occupies 0.42nm2. The number of electrons transferred per RIL molecule, n, is 2 and the transfer coefficient α of the irreversible adsorptive system of RIL is 0.71. The mechanism of electrochemical reduction of RIL at Hg electrode was explored. The detection limit of the adsorptive stripping voltammetry of RIL is 1.0×10-9mol·m-3 when the accumulation time is 3 min. on optimized condition.