03921 IUPAC Gold Book - migration current 10.1351/goldbook.M03921 M03921 current 1 The difference between the current that is actually obtained, at any particular value of the potential of the indicator or working electrode, for the reduction or oxidation of an ionic electroactive substance and the current that would be obtained, at the same potential, if there were no transport of that substance due to the electric field between the electrodes. The sign convention regarding current is such that the migration current is negative for the reduction of a cation or for the oxidation of an anion, and positive for the oxidation of a cation or the reduction of an anion. Hence the migration current may tend to either increase or decrease the total current observed. In any event the migration current approaches zero as the transport number of the electroactive substance is decreased by increasing the concentration of the supporting electrolyte, and hence the conductivity anion https://goldbook.iupac.org//terms/view/A00358 cation https://goldbook.iupac.org//terms/view/C00907 conductivity https://goldbook.iupac.org//terms/view/C01245 electroactive substance https://goldbook.iupac.org//terms/view/E01940 indicator https://goldbook.iupac.org//terms/view/I03006 migration https://goldbook.iupac.org//terms/view/M03920 oxidation https://goldbook.iupac.org//terms/view/O04362 supporting electrolyte https://goldbook.iupac.org//terms/view/S06149 transport number https://goldbook.iupac.org//terms/view/T06489 working electrode https://goldbook.iupac.org//terms/view/W06686 PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1497 (https://doi.org/10.1351/pac198557101491) https://goldbook.iupac.org/terms/view/M03921/html https://goldbook.iupac.org/terms/view/M03921/json https://goldbook.iupac.org/terms/view/M03921/plain Citation: 'migration current' 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.M03921 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. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . 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. 2026-04-21T05:27:45+00:00