New potassium-selective electrode based on an ionophoric bis(15-crown-5 ether) derived from xanthene-4,5-dicarboxylic acid

Abstract

Bis(15-crown-5 ether) derivatized from a xanthene-4,5-dicarboxylic acid skeleton was studied as an ionophore for a new K+-selective electrode. The polymeric liquid membrane based on this ionophore exhibits Nernstian behavior and optimization of experimental conditions for potentiometric analysis offers a wide linear dynamic range, reasonable detection limit, good durability and hysteresis within a limited error. Due to the well-preorganized structure, the selectivity over Na+ is comparable to those of commercialized K+-selective ionophores and the interferences by some cations such as Rb+ and Cs+ are reduced. Except slightly slow response, the enhanced recognition ability is reminiscent of the natural antibiotic valinomycin.