An ion-selective microelectrode for bile salts.

The development of a prototype ion-selective microelectrode for bile salts is described. The microelectrodes demonstrated Nernstian response (59 +/- 10 mV dec-1) with sodium deoxycholate in Tris (0.2 M, pH 9.0, 15-30 degrees C), HEPES (0.13 M, pH 7.5), and bicarbonate buffers (0.1 M, pH 7.5) (25 +/- 0.1 degrees C) were stable for several days, and the responses were highly reproducible. The microelectrodes were selective for bile salts over the physiologically important inorganic anions, bicarbonate and chloride. The response to sodium cholate (42 mV dec-1) was consistently lower than the ideal response (59 mV dec-1). This ion-selective microelectrode may show promise as a useful tool for the determination of intracellular bile salt activity.