The details of an impinging jet flow system to be used for interfacial electrochemical studies at smooth bead-type electrodes are described. The 0.7-ml min(-1) electrolyte flow was propelled by hydrostatic pressure and accurately controlled by a computer-controlled rotating valve. Carbon monoxide dissolved in 1 mol dm(-3) sulfuric acid was dosed onto a polycrystalline platinum surface in a carrier flow of pure electrolyte. The dosing performance of the flow cell was evaluated by electrooxidation of bulk and adsorbed CO, and the effect of dosing potential on the stripping voltammogram and on the charge displacement behaviour was investigated and discussed.