Electrical properties of glass microelectrodes

The electrical characteristics of a glass microelectrode can be designated as a parallel resistance and capacitance in series with a source of dc voltage. Measurement of these parameters depends upon the following factors: concentration, ionic species, pH, and the hydrostatic pressures of the electrolyte solutions inside the microelectrode and surrounding its tip. The physicochemical mechanism underlying microelectrode resistance and tip potential is interpreted as interaction of the surface charges of the glass and the conductivity of the solution inside the microelectrode. Methods for recording microelectrode resistance and tip potential, a method for filling microelectrodes at room temperature, and the automatic recording of microelectrode and tip potential are descried.