LIQUID JUNCTION POTENTIAL BETWEEN DIFFERENT SOLVENTS - A JUNCTION WITH AN ALKALI-METAL SALT AS ELECTROLYTE

The characteristics of the three components of a liquid junction potential between different solvents were studied at a junction with an alkali metal salt as the electrolyte. As for a junction with a tetraalkylammonium salt as the electrolyte, the equation previously reported for component (a) was proved to be valid in many cases. Component (b) at H2O/organic solvent and MeOH/dipolar aprotic solvent junctions also behaved similarly to that at a junction with a tetraalkylammonium salt. At junctions between aprotic solvents, however, lithium and sodium ions did not make an appreciable contribution to component (b), even when this was expected theoretically. This fact was found to be the cause of the apparently different behavior of component (c) in the case of salts of these metal ions. Thus component (c) can be considered to be almost independent of electrolyte species and concentrations, even when alkali metal salts are used as the electrolyte.