Cyclic voltammetric behaviour of α-(phenylthio)acetamides and α-(phenylthio)acetates were compared in CH 3 CN/tetrabutylammonium perchlorate (TBAP) and CH 3 CN/Et 3 N.3HF to assess the influence of fluoride ion on the oxidative pathway. These studies support the Pummerer mechanistic pathway involving an initial attack at sulfur in selective electrofluorination (SEF). A linear correlation between the peak current values in cyclic voltammetry and overall synthetic yield in preparative electrolysis was obtained suggesting the importance of weak blocking or a reactive adsorption effect on the overall synthetic processes. Other factors influencing the adsorption and insulation of electrode surfaces during the SEF are also discussed.