Reference electrodes for thick-film sensors

Paper deals with a problematic of thick-film electrochemical sensors for trace analysis of species or elements in aqueous solutions. A problem of replacement of classical Ag/AgCl reference electrodes by planar thick-film electrodes is discussed here. In this paper there were compared several thick-film reference electrodes with classical ones using the same electrochemical arrangement. Special commercial thick-film pastes and electrochemically fabricated Ag/AgCl layers were used for reference electrodes of thick-film electrochemical sensors and characterized in standard electrochemical solution of potassium ferro-ferricyanide. First results show big difference between tested materials, mainly in shifts of half weave potentials. Moreover with use of screen-printed reference electrodes, there was shown a high output current dependence on the change of electrodes distances.