“…The effect of interferences, due to the presence of electroactive as well as surface active species in the test solution, can be minimized by covering the indicator electrode with perm-selective membranes. Examples of such systems are the voltammetric membrane electrode systems used for the in situ measurements for dissolved oxygen (Mancy, Okun, and Reilley, 1962) or certain metal ions (Bowers et al, 1961). Potentiometric membrane electrode systems using glass or crystal membranes have been also used for measurements of specific cations and anions (Bowers et al, 1961;Rechnitz, Kresz, and Zamochnick, 1966).…”