{"term":{"id":"16254","title":"Nernstian response","longtitle":"IUPAC Gold Book - Nernstian response","doi":"10.1351\/goldbook.16254","code":"16254","status":"current","definitions":[{"id":1,"text":"Response of an ion-selective electrode according to a local thermodynamic equilibrium, over a given range of activity (or concentration) that follows the Nernst equation.","notes":{"1":"For the Nernstian response, the potential difference of the ion-selective electrode cell is proportional to the decadic logarithm of the ionic activity of a given species (\\(a_{\\rm{A}}\\)) with coefficient \\((RT\/z_{\\rm{A}}F)\/\\log_{10}(\\rm{e})\\) (about \\(0.0592\/z_{\\rm{A}}\\,\\pu{V}\\) at \\(\\pu{298.15 K}\\)), where \\(R\\) is the gas constant, \\(T\\) the thermodynamic temperature, \\(F\\) the Faraday constant, and \\(z_{\\rm{A}}\\) the electron number of an electrochemical reaction of species \\(\\ce{A}\\).","2":"Nernstian response implies ideal sensitivity, but not necessarily ideal selectivity, since interfering ions may also give a Nernstian response when they are present as the sole potential determining species."},"links":[{"term":"Nernst equation","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09068"},{"term":"electron number of an electrochemical reaction","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09063"}],"sources":["PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 665 (https:\/\/doi.org\/10.1515\/pac-2018-0109)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/16254\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/16254\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/16254\/plain"},"citation":"Citation: 'Nernstian response' 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.16254","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-04-20T14:01:20+00:00"}}