The electron transfer in the sulfonate desorption from Pt(111) can also be mediated by cations other than hydronium. When CVs were collected in 2 mM perchloric acid with different concentrations of sodium perchlorate, a peak shift rate of 56 ± 3 mV per order of magnitude change in the concentration of sodium cation (mV/dec(cation)) was determined (Figure ). This value is close to 59 mV/dec(cation) expected for a cation-assisted sulfonate desorption, as in Eq. 4: