| abstract |
Reference electrode for potentiometry maintains stable potential regardless of type or quantity of ions in a test soln. by using, between an internal soln. and a test soln., a high-polymer film element with a fine grain structure on the inside and a coarse grain structure on the outer, test soln. contact side. This element is suitably in the form of a field effect transistor, and is produced using a plasma polymerisation process. In an example, a field effect transistor channel portion (71) is provided with a drain (76) and source (77) and has successively laminated on it a ca. 100 Angstrom silver film (72), a ca. 500 Angstrom Ag2S + AgCl film, a ca. 500 Angstrom ion exchange resin film (74) and a ca. 1000 Angstrom film of inactive polystyrene that is formed by plasma polymerisation and centacts a test soln. (78). |