The research embodied within this thesis has contributed to the development and application of a novel electrode technique. The electrodes fabricated herein consist of a thin PVC/Poly (vinylchloride) membrane which is made sensitive to a particular organic cation, for example Acridine Orange. The only requirements necessary to make an electrode were that the substance to be incorporated into the membrane be cationic, water soluble and surface active. These membrane electrodes gave an emf directly proportional to the log of the ( concentration of organic cations present in solution.