All-solid-state reference electrodes with poly(n-butyl acrylate) based membranes

A new kind of all-solid-state reference electrode, suitable for potentiometry with ion-selective electrodes is proposed, where a poly(n-butyl acrylate) based membrane is coated on a glassy carbon support with conducting polymer-polypyrrole ion-to-electron transducing layer. These electrodes are compatible with poly(acrylate) based ion-selective electrodes in simple disposable cells, where both indicator and reference electrode can be produced in a single fabrication process, using the same or similar methods. The composition of the membrane with lipophilic salt and Ag/AgCl system was tuned to expose nonselectivity and to obtain a stable potential, independent of solution composition. Near-zero slopes of potentiometric characteristics were recorded in typical electrolyte solutions in the concentration range: 1 to 10(-5) M, stable potentials and only slight influence of interferents: oxygen, redox reactants, H+/OH- ions and surfactants make this arrangement promising for practical applications, particularly when matched against a similar ion-selective electrode. Tests of cells with poly(n-butyl acrylate) based membrane potassium selective sensors and reference electrodes confirmed their analytical applicability.