Counter-current chromatography. Applications to the separation of biopolymers, organelles and cells using either aqueous-organic or aqueous-aqueous phase systems

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

Ionic Liquid–Liquid Separations Using Countercurrent Chromatography: A New General-Purpose Separation Methodology

Liquid–liquid separations based on countercurrent chromatography, in which at least one phase contains an ionic liquid, represent a new empirical approach for the separation of organic, inorganic, or bio-based materials. A custom-designed instrument has been developed and constructed specifically to perform separations (including transition metal salts, arenes, alkenes, alkanes, and sugars) with ionic liquids, and has been demonstrated for use on the 0.1 to 10 g scale.

A new non-synchronous preparative counter-current centrifuge-the next generation of dynamic extraction/chromatography devices with independent mixing and settling control, which offer a step change in efficiency

A new and significantly more robust design of non-synchronous coil planet centrifuge is introduced where the degree of mixing between two immiscible phases can be changed independently from the "g" field required to separate out the phases. A hypothesis that an optimum ratio between the speed of the bobbin and the speed of the rotor can be found to optimise the efficiency of the separation for a given force field is upheld for an intermediate polarity phase system. This paves the way for extensive further research to find the optimum non-synchronous conditions for a range of different phase systems that are desirable for the separation of large molecules, proteins and biologics but can tend to emulsify in the standard "J" type centrifuge systems currently available and routinely in use for aqueous organic phase systems. A step change of up to 30% in resolution and 90% in plate efficiency is demonstrated.

Countercurrent chromatography: people and applications

The scientific literature was scanned for the published research articles dealing with countercurrent chromatography (CCC) over the time period 1980-May 2008. The search returned 1638 articles that were analyzed focussing on people and applications. Concerning the people, it was found that the geographical location of the CCC authors was relatively well balanced between USA, Asia with mainly China and Japan and Europe. Yoichiro Ito, the inventor of the technique, is by far the most productive author in the field with 331 articles or more than one over five CCC articles published in the time period. Without surprise, English is the dominant language with more than 82% of the articles. A significant 8% amount of CCC articles were published in Chinese in Chinese journals. Chromatography journals are the logical tribune for half of the published CCC articles. Concerning the applications, the separation and purification of natural compounds is the dominant theme in CCC making the subject of more than one article over two. Starting from the plant extract, CCC in few steps can produce significant amounts of more than 95% pure compounds used for identification and/or property studies. Other applications are found in the pharmaceutical and chemical field. The separation of enantiomers on the preparative scale is a field of growing importance.

Countercurrent separation of natural products

An assessment of the technology and method development in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CS), is provided. More than six decades of CS theory and applications are critically reviewed and developed into a practical guide to CS for natural products research. The necessary theoretical foundation is given for better use of CS in the separation of biological molecules of any size, small to large, and from any matrix, simple to complex. The three operational fundamentals of CS--instrumentation, biphasic solvent systems, and theory--are covered in a prismatic fashion. The goal of this review is to provide the necessary background and references for an up-to-date perspective of CS and to point out its potential for the natural products scientist for applications in natural products chemistry, metabolome, and proteome research involving organisms from terrestrial and marine sources.

Solvent systems for countercurrent chromatography: An aqueous two phase liquid system based on a room temperature ionic liquid

A new aqueous two phase liquid system (ATPS) based on the ionic liquid 1-butyl-3-methyl imidazolium chloride (BMIM Cl), potassium dibasic phosphate (K(2)HPO(4)) and water was recently proposed in the literature. The full phase diagram of this ATPS was prepared and some tie lines were fully determined. It was compared to classical ATPSs based on polyethylene glycol with an average molecular mass of 1000 (PEG 1000) and 10,000 (PEG 10000) and K(2)HPO(4). Two countercurrent chromatography (CCC) columns, a hydrostatic Sanki and a J type hydrodynamic CCC columns were used to test the liquid phase retention of these ATPSs in all possible configurations. It was found that the BMIM Cl ATPS liquid phases were much easier to retain in the two CCC columns than the PEG 1000 ATPS phases. Using protein and alcohol solutes, it was established that the BMIM Cl ATPS has a polarity completely different from that of the PEG 1000 ATPS. For example, ovalbumin partitions equally between the two phases of the PEG 1000 ATPS (K(D)=1.4) when it is completely located in the BMIM Cl upper phase of the ionic liquid ATPS (K(D)=180). The discrimination factor of the ionic liquid system and its intrinsic hydrophobicity were respectively found three times higher and ten times lower than the respective values of the PEG 1000 ATPS.

Separation of antibiotics by counter-current chromatography

This paper reviews recent applications of counter-current chromatography (CCC) to the separation of antibiotics. It also covers the recent development of CCC instruments and the optimization of the two-phase solvent system. The CCC technique offers a high resolving power when the proper solvent system is carefully selected and becomes a powerful tool to separate various components from antibiotics complexes.

Counter-current chromatography of lipoproteins with a polymer phase system using the cross-axis synchronous coil planet centrifuge

Lipoproteins were separated by counter-current chromatography using the type-XLL coil planet centrifuge. The separation was performed with a polymer phase system composed of 16% (w/w) polyethylene glycol 1000 and 12.5% (w/w) dibasic potassium phosphate by eluting the lower phase at a flow-rate of 0.5 ml/min. About 5 ml of the sample solution containing approximately 150 mg of a lipoprotein mixture were loaded. High- and low-density lipoproteins were resolved within 12 h. Each component was detected by gel electrophoresis with oil red staining.

Protein separation with aqueous-aqueous polymer systems by two types of counter-current chromatographs

Two different types of counter-current chromatographs, the cross-axis coil planet centrifuge (X-axis CPC) and horizontal flow-through coil planet centrifuge (horizontal CPC), were evaluated for protein separation with an aqueous-aqueous two-phase polymer system. The sample solution, containing 10-200 mg each of cytochrome c, myoglobin, ovalbumin and hemoglobin in 2 ml of each phase was eluted with the lower phase. In both instruments, the effects of the flow-rate, revolution speed, and parameter beta (helical diameters of the multilayer coil) on the protein separation were investigated. The best results were obtained from the X-axis CPC operated at 750 rpm and a flow-rate of 2.0 ml/min using a multilayer coil with a small helical diameter (beta = 0.25-0.60). Four protein samples were well resolved in less than 5 h.

Counter-current chromatography of black tea infusions

Counter-current chromatography using a multilayer coil planet centrifuge, with solvent system ethyl acetate-butanol-water, permits the separation of black tea infusions into fractions which include pure SII and a mixture of SI and SIa thearubigins. Good resolution of several components of the infusion may be achieved in elution times of 1 to 2 h. The appearance of chromatograms is altered on decaffeinating the infusion. The effect of stationary phase composition is considered. Resolution of the peaks improves with butanol content.

Multi-stage mixer-settler planet centrifuge. Preliminary studies on partition of macromolecules with organic-aqueous and aqueous-aqueous two-phase solvent systems

A rotary-seal-free planetary centrifuge holds a separation column which consists of multiple partition units (ca. 200) connected in series with transfer tubes. In the cavity of each partition unit the transfer tube extends to form a mixer which vibrates to stir the contents under an oscillating force field generated by the planetary motion of the centrifuge. Consequently, solutes locally introduced at the inlet of the column are subjected to an efficient partition process in each partition unit and separated according to their partition coefficients. The mixer tube equipped with a flexible silicone rubber joint was found to produce excellent results for partition with viscous polymer phase systems. The capability of the method was demonstrated on separation of cytochrome c and lysozyme using a PEG-aqueous dibasic potassium phosphate-aqueous two-phase solvent system.