Ruthenium Dioxide as High-Capacitance Solid-Contact Layer in K+-Selective Electrodes Based on Polymer Membrane

This article presents the fast and easy method of designing K + -selective electrodes with the use of ceramic nanoparticles.Ruthenium dioxide implemented into electrode's construction as a mediation layer turned out to exhibit remarkable electrical parametersevaluated with chronopotentiometry, electrochemical impedance spectroscopy and cyclic voltammetry methods -what resulted in noticeably high electrical capacitance of designed electrodes (1070 μF).This property of the material layer can be attributed to both redox reactions, in which ruthenium dioxide exchanges ions and electrons, and large surface area associated with nanometric size of RuO 2 particles.The potentiometric response of RuO 2 -contacted electrodes toward potassium ions was studied in the presence of coated-disc electrode without solid-contact layer.Since electrical parameters of electrodes determine their analytical performance, for electrodes of GCD/RuO 2 /K + -ISM type the linear range was wider (10 -6 to 10 -1 M), the potential response was more stable (with 0.085 mV potential value change per hour) and reversible in comparison with GCD/K + -ISM type.Developed potassium selective sensors were successfully applied for environmental samples analysis and the results obtained using potentiometry method were in good agreement with the reference method.