The Properties and Application of Cation-Responsive Glass Electrodes

Abstract

The comparatively recent development of glass electrodes primarily responsive to cations other than the hydrogen ion has opened up fresh analytical possibilities for the direct electrochemical measurement of sodium, potassium, ammonium, lithium and even divalent cations. Most work has been carried out on Na⁺- and K⁺- responsive systems, and the paper will describe the response ranges of typical glasses and the interferences to which they are subject. Attention will be given to techniques of usage for obtaining the best results.
Applications have so far mainly been concentrated in the biological sphere, where sodium and potassium measurements are of major importance both in research and routine clinical practice. Here the speed of measurement and opportunity for in vivo continuous monitoring are main attractions, particularly for sodium. However, other laboratory applications, e. g. for foods, water and analysis, etc. has been explored.
One industrial application is the continuous automatic determination of micromolar concentrations of sodium in high purity waters. Of interest here are the special techniques which are adopted to obtain stable and reproducible results in this concentration region.
Finally a brief indication will be given of some related new methods of specific ion measurement.