A Fast, Effective Method of Characterizing New Phase Systems in CCC

Abstract

This paper describes two simple tests that will characterize the hydrodynamics of a given phase system in a given CCC unit. Furthermore, it shows that, in practice, only one of these tests is necessary and the other can be predicted from the first. It goes on to show that retention information can be accurately obtained using a marker peak for the solvent front, so that both retention and resolution data can be collected in one simple test. While stationary phase retention (and, hence, peak elution) was found to behave quite predictably and could be modelled, resolution was not so predictable. Nevertheless, for analytical CCC, it was found that resolution of benzyl alcohol (BA) and p‐cresol (PC) only reduced from 2.3 to 1.4 as flow increased 7‐fold from 0.3 mL/min to 2 mL/min. Increasing the speed from 1000 to 2000 rpm (a 4× increase in “g” field) only increased the resolution a factor of 1.4×, whereas it was expected (from the number of mixing/settling cycles) to double. It is concluded that, for fast analytical CCC, it is worth running at as high a flow as possible (compensating for loss of resolution by increasing coil length) and increase speed only if it becomes necessary to obtain a reasonable retention.

Keywords:

• Countercurrent chromatography
• Liquid stationary phase retention
• Fundamental theory
• Resolution
• Flow rate

Acknowledgments

This research and the development of the Milli‐CCC were carried out with grant support from the EPSRC Grant No. GR/M48345 ID13, title “A New Rapid Centrifugal Liquid–Liquid Chromatography Separation and Detection System for Multiple High Resolution Purification Without Sample Loss or Degradation.” The authors are grateful to the EU INTAS programme No. 00‐0782 entitled “Fundamental Research into the Hydrodynamics and Efficiency of Counter‐Current Chromatography” for the financial support of this work and to Dr. P. Wood for valuable support and discussion.