Electrochemical reduction of Ge(IV) catalyzed by o-catechol at the dropping mercury electrode and at the hanging mercury drop electrode after adsorptive preconcentration

At low o-catechol concentrations, the behavior of the Ge(IV)-o-catechol electrocatalytic system differs significantly (particularly in its dependence on pH) when examined by DC polarography or by cyclic and square wave voltammetry following adsorptive preconcentration. This difference is ascribed to the fact that the catalytic complex is formed by a preceding chemical reaction and/or by direct adsorption when a hanging mercury drop electrode with an accumulation period is used whereas it is exclusively yielded by the first pathway when using a dropping mercury electrode.