Solid‐state sodium‐selective sensors based on screen‐printed Ag/AgCl reference electrodes

Abstract

Abstract The potentiometric and AC impedance characteristics of all solid‐state sodium‐selective electrodes based on planar screen‐printed Ag/AgCl electrodes are described. Two solid‐state designs have been investigated. The first was based on the deposition of a sodium‐selective PVC membrane directly on top of a screen‐printed Ag/AgCl electrode. The second design included a NaCl doped hydrogel layer, between the PVC and Ag/AgCl layers. The hydrogel provides a mechanism to relieve any blockage to charge transfer occurring when PVC membranes are used directly on top of Ag/AgCl and also improves adhesion between the two layers. Results suggest the electrodes display fast ion exchange kinetics, low noise and drift. The performance compares favorably to that of a conventional ion‐selective electrode with internal filling solution.