SOLID-STATE SODIUM-SELECTIVE SENSORS BASED ON SCREEN-PRINTED AG AGCL REFERENCE ELECTRODES/

The potentiometric and AC impedance characteristics of all solid-state sodium-selective electrodes based on planar screen-printed Ag/AgCl el ectrodes are described. Two solid-state designs have been investigated . The first was based on the deposition of a sodium-selective PVC memb rane directly on top of a screen-printed Ag/AgCl electrode, The second design included a NaCl doped hydrogel layer, between the PVC and Ag\A gCl layers. The hydrogel provides a mechanism to relieve any blockage to charge transfer occurring when PVC membranes are used directly on t op of Ag/AgCl and also improves adhesion between the two layers. Resul ts suggest the electrodes display Fast ion exchange kinetics, low nois e and drift. The performance compares favorably to that of a conventio nal ion-selective electrode with internal filling solution.