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

The characteristics of the three components of the liquid junction pot ential (ljp) between different solvents were studied at a junction wit h an alkaline earth metal salt as electrolyte. An equation was derived for component (a) at a junction with a Z(M)/Z(X) type electrolyte and its validity was confirmed experimentally using 2 + /1 - type Mg(ClO4 )(2), Sr(ClO4)(2) and Ba(ClO4)(2). Alkaline earth metal ions did not c ontribute appreciably to component (b) at a junction between two aprot ic solvents (even when more than 300mV was expected theoretically), bu t contributed to some extent at water\aprotic solvent junctions. Compo nent (c) was proved to be independent of electrolyte both at water\apr otic solvent and aprotic solvent\aprotic solvent junctions. (C) 1997 E lsevier Science S.A.