Liquid ion-exchanger microelectrodes

Figure 21-16 Photograph of a potassium liquid-ion exchanger microelectrode with 125 p.m of ion exchanger inside the tip. The magnification of the original photo was 400X. (From J. L. Walker, Anal. Chem., 1971, 43[i] 91 A. Reproduced by permission of the American Chemical Society.)...

Freiser, H., Coated wire ion-selective electrodes. In Ion-Selective Electrodes in Analytical Chemistry (H. Freiser, ed.), Vol. 2, Chapter 2. Plenum, New York, 1980. Fujimoto, M., and Kubota, T., Physicochemical properties of a liquid ion exchanger microelectrode and its application to biological fluids. Jpn. J. Physiol. 26, 631-650... 

K5. Khuri, R. N., Hajjar, J. J., and Agulian, S. K., Measurement of intracellular potassium with liquid ion-exchanger microelectrodes. /. Appl. Physiol. 32, 419-422 (1972). 

Wl. Walker, J. L., Ion specific liquid ion exchanger microelectrodes. Anal. Chem. 43, 89A-93A (1971). 

Liquid ion-exchanger microelectrode cocktail A 2.10 wt% Potassium tetrakis(4-chlorophenyl)borate 12.10 wt% Trioctylphosphine oxide... 

Open-tip liquid ion-exchange microelectrodes can be fabricated by pulling borosilicate glass capillary tubing to an appropriate tip diameter (0.5 to 1 /im),... 

The K" " values were not different using either liquid ion-exchanger microelectrodes or glass microelectrodes. We have also made extensive comparisons of activity measurements with the ion exchanger microelectrodes and concentration measurements using flame photometry and have found them to be entirely consistent (Cornwall, et al., 1970 Chow, et al., 1970). 

Orme, Frank. 1969. Liquid ion exchanger microelectrodes in Glass Microelectrodes. Ed. Marc Lavallee, Otto Schanne and Normand Hebert. John Wiley and Sons, New York. 

Potassium is the major determinant of the electrophysiological properties of cells- renal epithelial cells being no exception (Windhager and Giebisch, 1965). This study utilizes a double-barreled K" "-selective liquid ion-exchange microelectrodes to... 

Sodium and chloride are the major osmotic constituents of glomerular filtrate that need to be conserved by reabsorptive transport across the renal tubular epithelium. Double-barreled Cl -selective liquid ion-exchange microelectrodes were used to measure intracellular Cl concentration in single cellular elements of the proximal tubular epithelium. 

Fig, 1. Double-barreled, K -selective liquid ion-exchange microelectrode (diagrammatic). 

Using double-barreled liquid ion-exchange microelectrodes intracellular potassium and chloride concentrations were measured simultaneously with membrane PDs in single cells of the proximal tubules of Necturus kidney. The electrometric method measured an intracellular potassium concentration which constituted about 3/4 of the total K content. There was a remarkable agreement between the calculated and measured E across the luminal and peritubular boundaries suggesting passive transport of K", an electrochemical equilibrium distribution and K -selectivity of both membranes. 

The liquid ion-exchanger microelectrode consists in principle of a micropipette in which the internal wall of the tip-region is made organophilic-hydrophobic so that a column of the organic ion exchanger remains held there, when the rest of the inside of the electrode is filled with a conducting aqueous solution and the tip of the electrode is in tissue or a solution. The... 

Brown, A.M, Intracellular potassium and chloride activities measured with liquid ion exchanger microelectrodes. Brain Res. 1970, n, 433. 

Khuri, R.N., Aguilian, S.K, and Wise, W.M. Potassium in the rat kidney proximal tubules situ determination by K -selective liquid ion-exchanger microelectrodes. Pflug. Arch. Ges. Physiol. 1971, 3, 39. 

Walker, J.L., Jr. Ion Specific Liquid Ion Exchanger Microelectrodes. Anal. Chem., 1971, W, 89A. 

We have been using and Cl liquid ion exchanger microelectrodes to measure intracellular activities of K+ and Cl in frog heart. In these studies we have used three kinds of heart muscle ventricle, atrium and sinus venosus. The preparations are small pieces of tissue cut from the heart and pinned down in a chamber where they are superfused with frog Ringers solution. The ventricular and atrial preparations are quiescent unless stimulated in these experiments they are driven at a frequency of 0.5 stimuli/sec. The sinus venosus preparations are spontaneously active. 

Kraig, R. R, Nicholson, C., Sodium liquid ion-exchanger microelectrode used to measure large extracellular sodium transients. Science 1976, 194(4266), 725-726. 

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