Ion-selective electrode for measuring carbonate concentration

Abstract

An ion-selective electrode for measuring carbonate concentration comprising a conductive metal layer, a halide of said conductive metal layer, a carbonate ion-selective layer containing ion carrier, and a buffer layer containing a hydrophilic polymer binder and a buffer laminated in this order on an electrically insulating support, and a pair of the above electrodes. It is characterized by not having the electrolyte layer containing hydrophilic polymer binder, having the possibility of degradation of the electrolyte layer by the absorption of moisture being extremely little, and having a good stability in the course of time. In the electrode of the invention, the ion-selective layer comprised of hydrophobic organic material is directly laminated on the metal halide layer, the adhesive strength between the metal halide layer and the ion-selective layer is sufficient, the strength of the ion-selective layer is sufficiently great, and which is stable. The electrode of the invention has a sufficient buffering ability, and it requires neither operation of preliminary measurement of the pH value of aqueous liquid sample nor fixation of the pH value by adding a pH buffer to sample. Moreover, the adverse affect (measuring error) by the interfering substance such as salicylate, p-aminosilicylate or gentisate is eliminated or remarkably reduced.