Electroreduction of dipyridamole at mercury-coated platinum microelectrode

the electroreduction of dipyridamole (dip) was studied in 0.10 mol l-1 phosphate buffer solution (ph 3.0) on a mercury coated platinum microelectrode (hg-me), employing cyclic, linear sweep voltammetry and polarography techniques. the similarity between hg-me voltammetric profile and the sigmoidal polarographic waves both with a diffusion limited current is showed. experiments with a hanging mercury drop electrode (hmde) were performed in parallel to confirm the results obtained with hg-me, which indicated that the reduction occurs in two irreversible steps involving two electrons and two protons each step. the limiting diffusion current, concerning the first step, allows estimating the diffusion coefficient for dip as being equal to 2.04 x 10-5 cm2 s-1.