Countercurrent chromatography and the journal of liquid chromatography: A love story

Countercurrent chromatography (CCC) is a separation technique that works with a support-free liquid stationary phase. Since the mobile phase is also a liquid, biphasic solvent systems are used. The problem with CCC is due to its nature: it is difficult to maintain a stable liquid stationary phase when a liquid mobile phase is pushed through it. All modern CCC columns use centrifugal fields. The hydrodynamic CCC columns use open tubes coiled on spools that rotate in a planetary manner. The hydrostatic CCC columns use channels interconnected by ducts, mounted in a centrifuge rotor. It is difficult to work with a support-free liquid stationary phase, but the advantages of this chromatographic configuration are so important that it is worth finding better ways and to invent better CCC columns. The main advantage is that all injected compounds can access the whole volume of the liquid stationary phase, compared to the necessary solid-liquid interphase contacts with classical solid stationary phases. Saturation of the stationary phase, or column overload, is much more difficult in CCC than in classical preparative LC with silica gel based stationary phases. CCC is definitely a preparative technique. The other advantages of a liquid stationary phase include the wide range of polarities that can be obtained using the numerous available solvents and mixing them. No irreversible adsorption is possible in CCC, since the liquid stationary can always be recovered. These advantages and the modem commercially available CCC columns are presented in this article celebrating the 30th birthday of the Journal of Liquid Chromatography that always, with its editor, strongly supported the technique by publishing, at certain occasions, half of the whole scientific CCC production of the world.