Theoretical treatment of the dynamic response of ion-selective membrane electrodes

Summary

Soil samples whose pH had been adjusted to between 4.5 and 7.5 either for long periods in the field or short periods in the laboratory were incubated after wetting with water or 0.01 m CaCl2. Copper concentrations in the soil solutions decreased only slightly as the solution pH increased, but free cupric ion concentrations decreased considerably. The copper concentrations were smaller and the proportion of copper present in solution as cupric ion at a given pH was larger when CaCl2 rather than water was used. Complexed organic species made up most of the copper in all solutions. The duration of pH adjustment did not affect these results.



Copper adsorption isotherms were determined on the soils using low equilibrium solution concentrations. As a given copper concentration the quantity of copper adsorbed increased and the proportion of copper in solution present as cupric ion decreased with pH increase; again the duration of pH adjustment did not affect the results.

The effect of pH upon the copper and cupric ion concentrations in soil solutions

Response time curves of ion-selective electrodes

Theory and applications of ion-selective electrodes part II

I. PERSPECTIVE ON THE ROLES OF MEMBRANE ELECTROCHEMISTRY AND ELECTROANALYTICAL CHEMISTRY The thrust of electrochemistry in the past 25 years has been the study of electrode processes at blocked and unblocked electrodes, primarily metal/electrolyte interfaces. The vast literature which has been contributed by both physical and analytical chemists comprises a topic now known as electrodics to distinguish it from the more classical topics – electrochemical thermodynamics (the study of equilibrium and transport properties of electrochemical cells) and ionics (the study of equilibrium and transport properties of electrolyte solutions) – which occupied a significant number of chemists during the first 50 years of this century. Analytical electrochemists have found their interests expanding as they turn from analytical methodology to fundamental and applied studies within electrodics. Many practical contributions have been made in new and improved battery systems, fuel cells, electrochemical synthesis, electroly...

K. Tóth

Papers

Recent results on the dynamic response of precipitate-based ion-selective electrodes