An overview of recent progress in elution mode of counter current chromatography

• We presented an overview of the recent progress made in the elution mode of countercurrent chromatography (CCC).
• We summarized the major advantages and limitations of different elution modes of CCC.
• We described some novel elution modes developed for separation by CCC.
• We discussed the challenges of different elution modes of CCC applied to real samples.

Countercurrent chromatography (CCC) is a developing chromatographic technique that achieves separation based on the distribution of the target in an immiscible biphasic or multiphasic solvent system. In the past decades, this technique has advanced greatly in application and theory. This overview is mainly focused on the development of elution modes, which have been easily achieved with the classical CCC apparatus in recent years. It includes gradient elution, dual-mode elution, multiple dual-mode elution, recycling elution, extrusion elution, cocurrent elution and pH zone refining. The basic principles of each elution mode are described in detail and then summarized. The comparison and the scope of application of these elution modes are also discussed.