https://doi.org/10.1351/goldbook.D01817
The ratio of the total analytical concentration of a solute in the extract (regardless of its chemical form) to its total analytical concentration in the other phase.
Notes:
- If there is possible confusion with the @[email protected] or (mass) distribution ratio the term concentration distribution ratio (symbol \(D_\text{c}\)) should be used, but this is not common usage. This is reasonably compatible with chromatographic nomenclature.
- The terms @[email protected], @[email protected] and, where appropriate, @[email protected] @[email protected], @[email protected] @[email protected] are widely used alternatives but are not recommended. If they must be used in a given situation the term ratio is preferable to @[email protected]
- In equations relating to aqueous/organic systems the organic phase concentration is, by convention, the numerator and the aqueous phase concentration the denominator. In the case of @[email protected] ratio the opposite convention is sometimes used but should then be clearly specified.
- In the past there has been much confusion between the distribution ratio as defined above, the value of which varies with experimental conditions, e.g. \(\text{pH}\), presence of complexing agents, extent of achievement of equilibrium etc. and the true @[email protected] which is by definition invariable or the @[email protected] or @[email protected] which apply to a particular chemical species under specified conditions. For this reason the terms @[email protected], @[email protected], @[email protected], @[email protected] and @[email protected] constant should not be used in this context.
- The use of the ratio: light phase concentration to heavy phase concentration is ambiguous and is not recommended.
- The distribution ratio is an experimental parameter and its value does not necessarily imply that distribution equilibrium between the phases has been achieved.
Sources:
Orange Book, 2nd ed., p. 89 [Terms] [Book]
PAC, 1993, 65, 2373. (Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)) on page 2382 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 970 [Terms] [Paper]
Orange Book, 2nd ed., p. 89 [Terms] [Book]
PAC, 1993, 65, 2373. (Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)) on page 2382 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 970 [Terms] [Paper]