The Adsorption and the Influence of Modified beta-Cyclodextrins on the Kinetics of Several Electrode Reactions

The adsorption of modified _-cyclodextrins (_-CD) on the mercury electrode was investigated in NaClO4 solutions using differential capacity measurements. The investigated cyclodextrins revealed stronger affinity towards mercury electrodes than native_-CD. Their behaviour was typical for a monolayer and consistent with that predicted by the Frumkin isotherm. The electrode kinetics of Cu2+/Cu(Hg) and Cd2+/Cd(Hg) couples was significantly inhibited in the presence of modified _-CD in the solutions while much faster in surfactant free solutions the electrode process of Tl+/Tl(Hg) system remained reversible also in the presence of CD's.