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

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 lop of a screen-printed Ag/AgCl electrode. The second design included a NaCl doped hydrogel layer, between the PVC and Ag/AgCI layers. The hydrogel provides a mechanism to relieve any blockage to charge transfer occumng when PVC membranes are used directly on top of Ag/AgC1 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.

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