Solid state ion selective sensors: Conductimetric sensors using A.C. impedance and or admittance techniques as an alternative to potentiometric electrodes

摘要

A method of measuring the concentration of ions in a solution, for example the concentration of solvated H+ ions i.e. the pH, comprises applying an a. c. signal across an ion-sensitive material immersed in the solution and measuring the complex impedance of the ion-sensitive material at a frequency at which the out-of-phase component of the impedance is sensitive to changes in pH. A probe for use in the method comprises two metal electrodes encased in pH sensitive glass, or two electrodes coated independently with ion-sensitive glass, then fritted together.