Title: enrichment factor
Long Title: IUPAC Gold Book - enrichment factor
DOI: 10.1351/goldbook.E02127
Status: current
Index: quantity

Definition
The factor by which the ratio of two substances in the feed must be multiplied to give their ratio after treatment. \[\frac{Q_{\rm{A}}}{Q_{\rm{B}}} = S_{\rm{A,B}}\ \frac{Q_{\rm{A}}^{'}}{Q_{\rm{B}}^{'}}\] where \(Q_{\rm{A}}\) and \(Q_{\rm{A}}^{'}\) are the final and initial amounts of species A and \(Q_{\rm{B}}\) and \(Q_{\rm{B}}^{'}\) are the final and initial amounts of species B. Hence \(S_{\rm{A,B}}=\frac{E_{\rm{A}}}{E_{\rm{B}}}\) where \(E\) is the fraction extracted. In terms of \(D\),\(n\),\(r\) (where \(n\) is the number of stages and \(r\) the phase ratio), \[S_{\rm{A,B}} = \frac{1- (1\,+\,r\ D_{\rm{A}})^{-n}}{1- (1\,+\,r\ D_{\rm{B}})^{-n}}\]

Related Term
- fraction extracted: https://goldbook.iupac.org//terms/view/F02503

Sources
- Orange Book, 2nd ed., p. 90 (https://media.iupac.org/publications/analytical_compendium/)
- PAC, 1993, 65, 2373. 'Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)' on page 2382 (https://doi.org/10.1351/pac199365112373)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/E02127/html
- json: https://goldbook.iupac.org/terms/view/E02127/json
- xml: https://goldbook.iupac.org/terms/view/E02127/xml

Citation: Citation: 'enrichment 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.E02127
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Accessed: 2026-07-02T07:46:24+00:00