Preparation of iridium oxide and its application in sensor-actuator systems

✍ Scribed by W. Olthuis; J.C. van Kerkhof; P. Bergveld; M. Bos; W.E. van der Linden

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 507 KB
• Volume: 4
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(91)80191-l

✦ Synopsis

Acid or base concentrations can be determined by coulometric titration. A new alliridium oxide sensor-actuator device is presented, of which the titrant is generated by a reversible redox reaction occurring in the electroactive iridium oxide actuator electrode, and the equivalence point in the titration curve is detected by the pH-sensitive iridium oxide sensor. The advantage with respect to the formerly used noble metal actuator electrode/ISFET sensor device is twofold: on the one hand, interference of Cl-ions, which oxidize at the noble metal actuator electrode during titration, is avoided and on the other hand, the preparation of the all-iridium oxide device is easier than of the ISFET-based devices. In addition to the conventional potential sweep method of oxide growth, a new current-pulse method is proposed, of which the parameters for optimal growth depend less on the pH of the solution.