Title: potentiometric gas sensor
Long Title: IUPAC Gold Book - potentiometric gas sensor
DOI: 10.1351/goldbook.09123
Status: current

Definition
Ion-selective electrode cell that is responsive to an analyte gas.

Notes
1) The ion-selective membrane of the gas sensor is in contact with a thin film of solution that is separated from the bulk of the sample solution by a gas-permeable membrane or an air gap. This intermediate solution interacts with the analyte gas that penetrates through the membrane or air gap, which results in a change of a measured constituent (e.g., \(\ce{H+}\) activity) of the intermediate solution. This change is then sensed by the ion-selective electrode and is related to the partial pressure of the gaseous species in the sample.
2) These electrodes respond both to the partial pressure of the gas (\(\ce{H2}\) or \(\ce{Cl2}\)) and to the ionic activities of related species (\(\ce{H+}\) or \(\ce{Cl-}\)).
3) In electrochemical literature the term ‘gas electrode’ includes potentiometric gas sensors and the classical, redox-equilibrium-based gas electrodes, such as the hydrogen electrode: \(\ce{Pt(s)}\,|\,\ce{H2(g)\,|\,\ce{H+(aq)}}\).

Related Term
- ion-selective membrane: https://goldbook.iupac.org/terms/view/09119

Source
- PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 666 (https://doi.org/10.1515/pac-2018-0109)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09123/html
- json: https://goldbook.iupac.org/terms/view/09123/json
- xml: https://goldbook.iupac.org/terms/view/09123/xml

Citation: Citation: 'potentiometric gas sensor' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09123
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Accessed: 2026-06-28T02:17:26+00:00