Nickel hexacyanoferrate membrane as a coated wire cation-selective electrode

Abstract

Nickel hexacyanoferrates containing alkali metal cations as counter ions were used to prepare ion-selective electrodes for potentiometric sensing of intercalated species in the coated wire electrode (CWE) configuration. All the electrodes developed display a quasi-Nernstian response towards potassium ion, whereas the highest sensitivity is generally achieved when Cs⁺ is the counter cation in the sensing material. The selectivity constants of the electrodes were calculated by the matched potential method considering K⁺ as the primary ion. The selectivity order is Cs⁺ > K⁺ > Na⁺ > Li⁺ and reflects the effective dimension of the hydrated cations.