Reference electrode for electrochemical sensor - has platinum@ electrode coated with platinum oxide and polyhydantoin layers to function independently of oxygen@ partial pressure.

摘要

The novel features of a reference electrode consisting of a shaft (1) with an embedded Pt electrode (2) and used for electrochemical 3-electrode sensors are that (a) Pt electrode (2) is wholly or partly coated with Pt oxide (3); and (b) the Pt oxide layer (3) and opt. also the remaining Pt oxide-free parts of electrode (2) are wholly coated with a polyhydantoin layer (4). ADVANTAGE - The coating system functions independently of the surrounding partial O2 pressure and allows the sensor to be used for measurement of O2 or of gas mixts. in O2-free environments. Polyhydantoin layer (4) enables the formation of a Pt/PtO2 reference electrode of long term stability and of potential = 950 un V. Wetting of the electrode is also improved and the electrode is insensitive to gas in the measuring cell. Further, the electrode shows reduced response time and can be made easily with good reproducibility.