Term: relative retention, r
https://doi.org/10.1351/goldbook.R05277

Definition:
The ratio of the adjusted or net retention volume (time) or retention factor of a component relative to that of a standard, obtained under identical conditions: \[r=\frac{V_{\text{R}i}^{'}}{V_{\text{R}\left(\text{st}\right)}^{'}}=\frac{V_{\text{N}i}}{V_{\text{N}\left(\text{st}\right)}}=\frac{t_{\text{R}i}^{'}}{t_{\text{R}\left(\text{st}\right)}^{'}}=\frac{k_{i}}{k_{\text{st}}}\] Depending on the relative position of the peak corresponding to the standard compound in the chromatogram, the value of r may be smaller, larger or identical to unity.

Related Terms:
1) chromatogram (http://doi.org/10.1351/goldbook.C01071).

Source: Orange Book, 2nd ed., p. 105 (https://media.iupac.org/publications/analytical_compendium/)

Citation: 'relative retention, r' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.R05277

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.

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.