{"term":{"id":"05614","title":"separation factor","longtitle":"IUPAC Gold Book - separation factor","doi":"10.1351\/goldbook.S05614","code":"S05614","status":"current","synonym":"<em>synonym<\/em>: separation coefficient","index":"quantity","definitions":[{"id":1,"text":"The relative retention value calculated for two adjacent peaks (\\(V_{\\rm{R}2}^{'}>V_{\\rm{R}1}^{'}\\)): \\[\\alpha =\\frac{V_{\\rm{R}2}^{'}}{V_{\\rm{R}1}^{'}}=\\frac{V_{\\rm{N}2}}{V_{\\rm{N}1}}=\\frac{t_{\\rm{R}2}^{'}}{t_{\\rm{R}1}^{'}}=\\frac{k_{2}}{k_{1}}\\] By definition, the value of the separation factor is always greater than unity. The separation factor is also identical to the ratio of the corresponding distribution constants. The separation factor is sometimes also called the 'selectivity'. The use of this expression is discouraged.","contexts":[],"links":[{"term":"selectivity","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/S05564"}],"sources":["PAC, 1993, 65, 819. 'Nomenclature for chromatography (IUPAC Recommendations 1993)' on page 844 (https:\/\/doi.org\/10.1351\/pac199365040819)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/S05614\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/S05614\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/S05614\/plain"},"citation":"Citation: 'separation factor' 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.S05614","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":"2026-05-12T10:22:15+00:00"}}