Response Properties, Applications and Limitations of Carbonate-selective Polymer Membrane Electrodes

The preparation and response characteristics of a carbonate-selective polymer membrane electrode are reported. The electrode is prepared by incorporating Aliquat 336, trifluoroacetyl-p-butylbenzene and di-2ethylhexyl sebacate or dioctyl phthalate in a poly(vinylchloride) membrane matrix. The effect of membrane composition and electrode response in various buffer systems are examined. Under buffer conditions appropriate for practical measurements, potentiometric data yield the following sclcctivity pattern: CIO; = salicylate > total carbon dioxide species > I> NO; > acetate > Cl> Br: The electrode can be readily fabricated in tubular form and utilized within a very simple flow-injection arrangement to determine total carbon dioxide species. The possible applications of the electrode to serum CO, measurements as well as within newly devised gas-sensing arrangements for dissolved CO, are also examined.