Ohmic drop effects in square-wave voltammetry response for an ion transfer process at a liquid–liquid interface

Abstract

The effect of ohmic drop on square-wave voltammetry experiments (SWV) at a liquid–liquid interface is analyzed. The study is based on the distortion of SW voltammetric profiles of the tetraethyl ammonium transfer process across the water/1,2-dichloroethane interface when an uncompensated resistance, R Ω , is present. Depending on the experimental conditions significant R Ω values arise as a consequence of the low electrical conductivity of the organic solvent characteristic of these systems, and efficient IR compensation is needed. When R Ω is not totally removed, a non-linear dependence of peak current (Δ I p) on the square root of the frequency, an increase of half-peak width (Δ E p/2) and a shift of peak potential ( E p) towards more positive values are observed in the SW profiles. The influence of signal frequency and R Ω values on SWV parameters (Δ I p, E p and Δ E p/2) is evaluated.