10040 IUPAC Gold Book - retention time of an unretained compound 10.1351/goldbook.10040 10040 current 1 Retention time of a sample component the molecules of which are larger than the largest pores of the particles of the stationary phase. This component will be eluted first from the column. The retention time of an unretained compound is related to the retention volume of an unretained compound (in size-exclusion chromatography) and the flow rate (\(F_{\rm{c}}\)) by \(t_{0} = V_{0}/F_{\rm{c}}\) Retention time https://goldbook.iupac.org//terms/view/16259 PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 212 (https://doi.org/10.1515/pac-2017-0111) https://goldbook.iupac.org/terms/view/10040/html https://goldbook.iupac.org/terms/view/10040/json https://goldbook.iupac.org/terms/view/10040/plain Citation: 'retention time of an unretained compound' 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.10040 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. 2026-07-27T20:12:07+00:00