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Elution‐extrusion counter current chromatography extrudes the most solute retained in the column with the highest possible peak resolution. It can greatly improve the hydrophobic window. In recent years, elution‐extrusion counter current chromatography has received extensive attention in the separation of complex samples. This article first reviews the development and application of elution‐extrusion counter current chromatography, including its origin, mechanism, advantages and disadvantages, and some representative applications. At the same time, this review also shared our visions and ideas on how to improve the elution‐extrusion mode. This article aims to provide certain reference for the research of this technology. [ABSTRACT FROM AUTHOR]

Alkaloids, widespread in plants, have a series of pharmacological activities and have been widely used to treat various diseases. Because alkaloids are usually presented in multicomponent mixtures and are deeply low in content, they are very difficult to extract and separate by traditional methods. High-speed counter current chromatography(HSCCC) is a kind of liquid-liquid chromatography without solid support phase, which has the advantages of large injection volume, low cost, and no irreversible adsorption. Compared with the traditional methods of extraction and separation of alkaloids, HSCCC can ensure the separation of many different alkaloids at one time, with a high recovery and large amount. In this paper, the advantages and disadvantages of HSCCC compared with traditional separation methods were discussed and the solvent system and elution mode of HSCCC used to separate alkaloids in recent years were summarized by referring to the relevant literature to provide some references for the separation of alkaloids by HSCCC.

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. [ABSTRACT FROM AUTHOR]

Hydrophilic organic/salt-containing aqueous two-phase system composing of ethanol, water and ammonium sulfate for separation polar compounds was investigated on multilayer coil associated with J-type HSCCC devices. Compared to the classical polar solvent system based on 1-butanol-water or PEG1000-ammonium sulfate-water, the water content of upper phase in ethanol-ammonium sulfate-water systems was from 53.7% to 32.8% (wt%), closed to PEG1000-ammonium sulfate-water aqueous two-phase systems and higher than 1-butanol-water (22.0%, wt%). Therefore, the polarity of ethanol-ammonium sulfate-water is in the middle of 1-butanol-water and PEG-ammonium sulfate-water system, which is quite good for separating polar compounds like phenols, nucleosides and amino acids with low partition coefficient in 1-octanol-water system. The retention of stationary phase in four elution mode on type-J counter-current chromatography devices with multilayer coil column changed from 26% to 71%. Hydrodynamic trend possess both intermediate and hydrophilic solvent system property, which closely related to the composition of solvent system. The applicability of this system was demonstrated by successful separation of adenosine, uridine guanosine and cytidine. [ABSTRACT FROM AUTHOR]

Abstract: Counter-current chromatography (CCC) has been widely used as a preparative chromatography technique since Ito first developed it in the late 1960s. This technique uses a support-free liquid stationary phase, which is retained by gravity or centrifugal force. The analytes can access the whole stationary phase, leading to effective separation. In the past few decades, high-speed CCC has been a versatile preparative-scale separation technique, especially in isolation of natural products. The aim of this review is to describe different aspects of recent interesting applications in CCC, including instrumentation, solvent selection and elution methods. [Copyright &y& Elsevier]

Countercurrent chromatography is a powerful separation technique, which is used as an alternative or complementary technique to other chromatographic methods due to its high efficiency and preparative capacity. This technique does not require a solid stationary phase and relies simply on the partition of a sample between the two phases of an immiscible solvent system. Thus, it eliminates the complications resulting from the solid support matrix, such as irreversible adsorptive sample loss and deactivation, tailing of solute peaks, and contamination. With these advantages, CCC is gaining popularity as an important separation method. This review summarizes the basic principles and gives the most recent CCC applications in various areas, including the isolation and purification of natural products, development of different elution modes and multidimensional methods, progress in pH-zone-refining CCC techniques, bioseparation with aqueous polymer two-phase systems, enantioseparation with various efficient chiral selectors, and on-line monitoring of the eluate. [ABSTRACT FROM AUTHOR]

Hydrophilic organic/salt-containing aqueous two-phase system composing of ethanol, water and ammonium sulfate for separation polar compounds was investigated on multilayer coil associated with J-type HSCCC devices. Compared to the classical polar solvent system based on 1-butanol-water or PEG1000-ammonium sulfate-water, the water content of upper phase in ethanol-ammonium sulfate-water systems was from 53.7% to 32.8% (wt%), closed to PEG1000-ammonium sulfate-water aqueous two-phase systems and higher than 1-butanol-water (22.0%, wt%). Therefore, the polarity of ethanol-ammonium sulfate-water is in the middle of 1-butanol-water and PEG-ammonium sulfate-water system, which is quite good for separating polar compounds like phenols, nucleosides and amino acids with low partition coefficient in 1-octanol-water system. The retention of stationary phase in four elution mode on type-J counter-current chromatography devices with multilayer coil column changed from 26% to 71%. Hydrodynamic trend possess both intermediate and hydrophilic solvent system property, which closely related to the composition of solvent system. The applicability of this system was demonstrated by successful separation of adenosine, uridine guanosine and cytidine., (Copyright © 2014 Elsevier B.V. All rights reserved.)