Separations with a Liquid Stationary Phase: Countercurrent Chromatography or Centrifugal Partition Chromatography

Ever since Yoichiro Ito reported the separation of blood plasma cells with a sealed helical tube in 1966, countercurrent chromatography (CCC) has been a fertile ground for instrumental and technical innovations. The key innovation of CCC was to use centrifugal forces to retain the stationary liquid phase in the column in such a way that it can interact dynamically with mobile phase without any solid support. The great diversity of countercurrent separation terminology reflects both the innovative spirit of the field and the global appeal of this technique. The selected biphasic liquid system is the core of the CCC technique. The CCC columns must be able to generate the centrifugal field needed to maintain the liquid stationary phase. They cannot be a simple tube with frits at both ends. Rotors, gears, spools, and rotating seals are very specific things that are not needed in classical LC with a solid stationary phase. This chapter describes the commercially available CCC columns and few practical examples. The special terminology used in CCC is explained sorting terms into three classes: the terms linked to the CCC instrumentation, the terms linked to CCC operation, and the terms coming from the biphasic liquid system. Keywords: centrifugal partition chromatography; countercurrent chromatography; liquid stationary phase