A finite-element method for determining ohmic distortion of current-voltage curves at hydrodynamic electrodes

A finite‐element method is described that predicts the effects of ohmic distortion of current‐voltage curves for arbitrary cell and hydrodynamic electrode geometries using the widely available circuit analysis program SPICE. Simulated and experimental data are presented for a channel electrode flow cell showing the displacement of the half‐wave potential and the potential‐dependent error in the Tafel slope for the case of an electrochemically reversible electrode reaction. Error curves are provided that may be scaled for different electrolyte conductivities as a guide to the maximum current levels that may be used in practice. For analytical flow detection work, the displacement of the half‐wave potential under certain conditions implies that high detection potentials must be used to obtain the correct concentration‐related current intensity. The implications for quantitative measurements using practical electrodes are assessed.