Is there still a need for the antimony electrode 100 years after its introduction as a pH sensor?

Although the glass electrode, first mentioned in the literature over 100 years ago, is still the preferred analytical tool for determining hydrogen ion activity in aqueous media, there are a number of applications for other sensors that also measure pH. Even if they do not correspond to the measuring performance of the glass electrode in terms of, e.g., accuracy, reproducibility, and long-term stability, they open up the feasibility of using electrochemical sensors even where the operation with glass electrodes is not possible. This applies in particular to scenarios in which extreme and harsh environmental conditions prevail. Currently relevant here are, for example, measurements in geothermal plants or directly on arable land in agricultural production. In the present article, new electrochemical devices based on antimony electrodes are presented especially for these purposes; in addition, the use of the antimony electrode as a basic electrode for the CO 2 determination according to the Severinghaus principle is reported on.