## fraction extracted, E

https://doi.org/10.1351/goldbook.F02503
The fraction of the total quantity of a substance extracted (usually by the solvent) under specified conditions, i.e. EA = QA.Q'A where QA is the mass of A extracted and QA' is the total mass of A present at the start.
Notes:
1. E may be expressed as a percentage, %E.
2. The term extractability is qualitative and should not be used as a synonym for fraction extracted.
3. If the aqueous phase is extracted with n successive portions of solvent, the phase volume ratio (solvent/feed) being r each time, the fraction extracted is given by: $E_{n} = 1 - \left ( rD + 1 \right )^{-n}$ If n = r = 1 and E1 = D/(1 + D) this expression is a concept of value in @[email protected] theory.
4. The fraction extracted is also known as the @[email protected] factor, especially for a multistage process.
Source:
PAC, 1993, 65, 2373. 'Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)' on page 2384 (https://doi.org/10.1351/pac199365112373)