Measuring Cation Activity of Living Brain

Abstract

DETROITRecent development of special glasses capable of discriminating sodium and potassium ions has made possible a method for recording the concentration of these ions in vivo. [4][5][6]8,9 Electrodes made from these glasses function exactly like the common pH (hydrogen ion) electrode. In fact, in an acid solution, the sodium and potassium electrodes may be used to measure pH. However, in a sodium or potassium salt solution above pH 6, the response to hydrogen ion activity is negligible and the electrodes respond essentially only to changes in sodium or potassium ion activity. In the same manner a pH electrode will respond to changes in sodium and potassium ions above pH 11.

The assay of free potassium in biological buffers with a K+-selective glass electrode

“…Biological work is usually carried out at neutral pH, and although K+ -selective glass electrodes have been used for many years in biological research (Hinke, 1959(Hinke, , 1961Khuri el al., 1963;Portnoy et al, 1963;Lev, 1964;Jacobson, 1966;Lambert and Hammond, 1973;Gale, 1974;Kroll and Anagnostopoulos, 1981;Borst-Pauwels and Theuvenet, 1985;Theuvenet et al, 1987), there is no detailed study of its performance in neutral 1 -100 mM TRIS-HCl pH 7.20; 3-100 mM imidazole--HCl pH 6.50; 5-10 mM TRIS-DMGA pH 7.00; 7 -10 mM Ca 2 + -PIPES pH 6.50; 2 -20 mM imidazole-HCl pH 6.50 4 -1 mM Mg 2 + -PIPES pH 6.50 6 -100 mM ethanolamine-DMGA pH 6.50 8 -10 mM Ml+ -PIPES pH 6.50 9 -10 mM Na + -DMGA pH 6.50; 10 -10 mM Na +-PIPES pH 6.50…”