Distribution discontinuous counter-current

Separating funnels for batch extraction special glass apparatus for continuous extraction automatic shakers used for discontinuous counter-current distribution. 

Liquid-liquid partition methods referred to in the previous chapter can be extended even to the separation of solutes possessing only small differences in their partition coefficients by a method called counter-current distribution. The technique of counter-current distribution, developed mainly by Craig, is a multiple partition process with a large number of stages, entirely discontinuous and stepwise in nature. 

S. 1.1.1. Counter-current Distribution as a Discontinuous Model of Chromatography... 

Counter-current distribution represents a discontinuous model of one of the types of chromatography, namely partition chromatography. Let us start from a simple liquid extraction in a separating funnel After equilibrium has been attained, the ratio of the amounts of substance in the two phases (identified by subscripts, and respectively) is given by a (u,/u ). where a is the partition coefficient (concentration ratio c./c ) and v denotes the volumes of both phases. Complete separation of a mixture of solutes cannot be achieved unless we are dealing with two solutes only, one of th exhibiting a = 0 and another a = oo. 

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