Term: enrichment factor, \(S\)
https://doi.org/10.1351/goldbook.E02127

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

Related Terms:
1) fraction extracted (http://doi.org/10.1351/goldbook.F02503).

Source: Orange Book, 2nd ed., p. 90 (https://media.iupac.org/publications/analytical_compendium/)

Citation: 'enrichment factor, \(S\)' 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.E02127

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