Installing High Performance Counter Current Chromatography in your Laboratory

The schematic installation diagram shows how simply a high performance counter current chromatography (HPCCC) unit can be incorporated within your laboratory. Typically when people are first introduced to using a HPCCC unit they are told to treat it just as a different type of column and simply install it in an existing liquid chromatography (LC) system (HPLC, Flash), replacing the solid stationary phase (SP) column. The primary alteration to the system is the fitting of a restrictor downstream of the pumps, if the pumps currently operate at high pressures, because HPCCC works at significantly lower pressures than HPLC.

Once installed the simple steps of working with HPCCC are as follows: select the preferred solvent system, make up the solvent system, prepare the counter current chromatography instrument and perform the separation (detailed operating instructions are available). However, the following needs to be noted regarding sample preparation and injection. The sample for injection can be made-up in either the MP or SP, as long as the equilibrium of the solvent system is not disturbed. It is recommended to dissolve sample in a mixture of both phases. In any case, all compounds in the sample must be brought in solution by use of one or both phases.

The typical size of the sample loop is 5% of the column volume. If at this loading you are achieving good separation then you may increase loading further, but it is always better to achieve this increase by further increasing the volume of sample injected. It is possible to dissolve samples in larger volumes where solubility problems are encountered; however, this will cause a loss in resolution, but this can be compensated for by increasing the length of column used.

The pressure of the instrument should be monitored while the sample is injected and throughout the run. This is especially important on the analytical scale machine where a rapid, but small change in pressure can cause a loss of SP and an impact on the resolution of the separation.