Preferred Label : distribution ratio;
Detailed label : distribution ratio in liquid-liquid distribution, D;
IUPAC definition : 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.;
Scope note : 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 stripping ratio the opposite convention is sometimes used but should
then be clearly specified.; if there is possible confusion with the extraction factor or (mass) distribution ratio
the term concentration distribution ratio (symbol dc) should be used, but this is
not common usage. this is reasonably compatible with chromatographic nomenclature.; the distribution ratio is an experimental parameter and its value does not necessarily
imply that distribution equilibrium between the phases has been achieved.; the use of the ratio: light phase concentration to heavy phase concentration is ambiguous
and is not recommended.; 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. ph, presence of
complexing agents, extent of achievement of equilibrium etc. and the true partition
coefficient which is by definition invariable or the partition coefficient or distribution
constant which apply to a particular chemical species under specified conditions.
for this reason the terms distribution constant, partition constant, partition coefficient,
partition ratio and extraction constant should not be used in this context.; the terms distribution coefficient, extraction coefficient and, where appropriate,
scrubbing coefficient, stripping coefficient are widely used alternatives but are
not recommended. if they must be used in a given situation the term ratio is preferable
to coefficient.;
Origin ID : D01817;
See also
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.
