SOME RECENT STUDIES ON THE USE OF ELECTROCHEMICAL SENSORS IN NONAQUEOUS SOLUTION CHEMISTRY

Four recent studies in the authors' laboratory on the use of electrochemical sensors in nonaqueous solutions are reported. (1) Si3N4- and Ta2O5-type ISFETs proved to be useful in nonaqueous solutions as sensors for pH and for proton solvation, because of their more rapid response than a conventional glass electrode. They were used to study the acid-base equilibria in gamma-butyrolactone and to determine the proton transfer activity coefficients between different solvents. (2) A univalent cation-sensitive glass electrode was used to study the solvation of lithium ions in mixed solvents applicable to lithium batteries. (3) A membrane of polyacrylamide coupled to a cobalt phthalocyanine complex and coated onto a platinum electrode functioned as a sensor for fluoride and cyanide ions in aprotic solvents. It was used to determine the solubility products of alkali and alkaline earth metal fluorides and cyanides in acetonitrile and propylene carbonate. (4) A new method is proposed for the estimation of the liquid junction potential between different solvents, and a comparative study has been made between the new method and some conventional methods.