Effect of ionic strength on the formal potential of the glass electrode in various saline media

Abstract

We examined the variation with ionic strength (I, adjusted with KCl, KNO3, KBr, NaCl or NaClO4) of the formal potential (Econst) for glass electrodes exhibiting a Nernstian response (i.e. Ecell=Econst−s log [H+]). For this purpose, we investigated the different factors included in the formal potential, so we obtained reported values for the liquid junction potential as a function of ionic strength and determined the logarithm of the activity coefficient for the proton in various saline media, using Pitzer equations.