VOLTAMMETRIC DETERMINATION OF UBIQUINONE ADSORPTION AT MERCURY-ELECTRODES

Adsorption isotherms of the ubiquinones UQ(4), UQ(6), UQ(9) and UQ(10) have been determined by two independent voltammetric techniques at th e stationary mercury/solution interface. While the redox behavior is e ssentially the same for all homologues investigated, the molar free en thalpy of adsorption Delta(A)G increases steadily with the number of i soprenic units from UQ(4) to UQ(10). In case of UQ(10), the experiment s have been carried out with three different potentiostatic systems. T his allows one to estimate the accuracy of the methods which are direc t ones and do not require calibration.