ON THE SEVENTIETH ANNIVERSARY OF THE “SUSPENSION EFFECT”:
A REVIEW OF ITS INVESTIGATIONS AND INTERPRETATIONS

Srečko F. Oman
Faculty of Chemistry and Chemical Technology, University of Ljubljana,
Aškerčeva 5, 1000 Ljubljana, Slovenia
 

ABSTRACT

A short critical review of Suspension Effect (SE) studies since its naming up to the present and the causes of the lack of a consensus about its origin and nature are given.
An argued (operational) SE definition and an interpretation based on this are presented considering the SE as the sum of two effects, one as the occurrence of the irreversible mixed potential of the indicator electrode and one as the anomalous liquid junction potential at the contact of the reference electrode salt bridge with the suspension. In systems subject to the SE the ion activities are not determinable rigorously; however their estimation could be useful as shown by "soil pH" determinations.