Theoretical study of separation and concentration of solutes by closed-loop recycling liquid-liquid chromatography with multiple sample injection

- Simple equations to simulate separations with multiple sample injection.
- Several possible implementations of multiple feed injection.
- Simultaneous separation and concentration of the target component.
- The technique may be especially useful to determine minor impurities.

The method of closed-loop recycling counter-current chromatography (CLR CCC) with multiple sample injection is proposed for the separation and concentration of a target component of a mixture. Analytical expressions are developed to describe the CLR CCC separations with multiple sample injection. Several possible implementations of multiple feed injection are analyzed: the feed is injected in each cycle, after every two cycles and in an arbitrary cycle. The application of different modes of multiple feed injection to the separation and concentration of the target component from binary mixtures by CLR CCC has been studied. The results of this study indicate that it is possible to achieve simultaneously both the separation and concentration of the target component.