In this paper, the function and electric properties of the ternary hybrid system glass/polypyrrole/Pt as solid inner contact for an all-solid-state pH glass electrode were examined. Polypyrrole (PPy) with chloride or nitrate doping was coated chemically onto pH-sensitive silicate glasses with high lithium content. The composite made of the two polymers polypyrrole and Nafion(R) shows favourable properties for pH sensor applications. (C) 2003 Published by Elsevier B.V.