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PubMed2005

Effect of gravitational force on type-J counter-current chromatography by mathematical analysis.

The gravitational force exerts an important effect on the counter-current chromatography (CCC) and has been used to retain the stationary phase and improve the efficiency in the various CCC separations. This paper deals with the effect of gravitational force on type-J CCC, one of the most popular CCC methods by the mathematical analysis for the first time. The theoretical analyses reveal a close relationship between the effect of gravitational force, the placed orientation of type-J CCC apparatus, and the revolutional speed. Two placed orientations are more suitable for preparative CCC separation: one is common horizontal, and the other upright. Thus, there are three optimum conditions for type-J CCC separation, the first using horizontal apparatus at very low revolutional speed around 10rpm in the gravitational filed, the second by use of upright apparatus at moderate revolutional speed around 100rpm in the three-dimensional complex force field composed of centrifugal and orthogonal gravitational force, and the third employing the apparatus placed at any orientation including horizontal and upright CCC apparatus at high revolutional speed above 300rpm in the centrifugal force field. Therefore, we should consider the effect of gravitation force on CCC at the selection of proper operational conditions according to properties of two immiscible phases, the desired revolutional speed and the parameters of apparatus in order to utilize efficiently the effect of gravitational force. These analyses and results will benefit to improve the efficiency of CCC separation, especially large-scale industrial preparation.

Countercurrent Distribution↗
PubMed2005

Preparative isolation and purification of four compounds from the Chinese medicinal herb rhizoma Anemarrhenae by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was applied to the separation and purification of mangiferin, neomangiferin, cis-hinkiresinol and (-)-4'-O-methylnyasol from the Chinese medicinal herb rhizoma Anemarrhenae. Five hundred milligrams of crude extracts were separated by using n-butanol-acetic acid (1%) (1:1, v/v) as the two-phase solvent system and yielded 35.3 mg of neomangiferin and 245.4 mg of mangiferin. During this separation, cis-hinkiresinol and (-)-4'-O-methylnyasol were still maintained in the stationary phase. The stationary phase was collected, evaporated to dryness and separated with light petroleum-ethyl acetate-methanol-water (1:1:1.2:0.8, v/v) and 1:1:1.4:0.6 (v/v) in gradient elution, which yielded 17.2 mg of cis-hinkiresinol and 12.4 mg of (-)-4'-O-methylnyasol. The purities of mangiferin, neomangiferin, cis-hinkiresinol and (-)-4'-O-methylnyasol were 96.3, 98.0, 97.3 and 98.2%, respectively, as determined by HPLC. The chemical structures of these components were identified by 1H NMR and 13C NMR.

Anemarrhena↗
PubMed2005

Preparative separation of cichoric acid from Echinacea purpurea by pH-zone-refining counter-current chromatography.

pH-zone-refining counter-current chromatography was successfully applied to the separation of cichoric acid from Echinacea Purpurea (L.) Moench. A 3.0 g quantity of sample was separated using the following two-phase solvent system: MtBE-CH3CN-water (4:1:5, v/v), 10 mM trifluoroacetic acid in organic stationary phase and 10 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by high-performance liquid chromatography and negative ion electrospray ionization mass spectrometry. Double separations were performed with the same solvent system yielding 563 mg cichoric acid at 95.6% purity.

Caffeic Acids↗
PubMed2006

New small-scale cross-axis coil planet centrifuge. The design of the apparatus and its application to counter-current chromatographic separation of proteins with aqueous-aqueous polymer phase systems.

The cross-axis coil planet centrifuge (X-axis CPC) is useful for partitioning macromolecules with aqueous-aqueous polymer phase systems. The floor model we have built with a pair of separation columns had some shortcomings such as requirement of large space, short life of the flow tubes, and difficulty in installing columns. In order to improve the partition efficiency and the utility of counter-current chromatography (CCC), a new small-scale X-axis CPC was designed and fabricated in our laboratory. The down-sizing of the apparatus was done by reducing the scale to about 1/2 of our original model of X-1.5L type with several improvements. Performance of the apparatus was evaluated on protein separation using an aqueous-aqueous polymer phase system composed of polyethylene glycol 1000 and dibasic potassium phosphate with four multilayer coiled columns. A series of experiments revealed that the combination of right- and left-handed coils produced the best partition efficiencies for both lower and upper mobile phases by selecting the revolution direction. The overall results indicate that the head-tail elution mode substantially affects to the peak resolution and stationary phase retention. This new X-axis CPC would be useful for the separation of various kinds of biologically active compounds.

Centrifugation↗
PubMed2006

Application of cellulose and amylose arylcarbamates as chiral selectors in counter-current chromatography.

Here we studied the applicability of cellulose and amylose tris(3,5-dimethylphenylcarbamate) as chiral selectors for the separation of enantiomers by counter-current chromatography (CCC). A variety of organic/aqueous biphasic solvent systems and eight racemic analytes of acidic, neutral, and basic nature were tested for this purpose. Classical elution mode and pH-zone-refining displacement conditions were used. Partial enantioseparation of pindolol and warfarin was achieved in methyl isobutyl ketone (MIBK)/aqueous solution and methyl tert-butyl ether (MTBE)/aqueous solution, respectively. For these two racemates enantiomeric excess values from 84% to 97% were achieved under the best conditions tested. However, resolution by CCC was not achieved for propranolol, naproxen and N-(3,5-dinitrobenzoyl)-(+/-)-leucine, easily separated in HPLC by the same selectors.

Amylose↗
PubMed2006

Application of dual counter-current chromatography for rapid sample preparation of N-methylcarbamate pesticides in vegetable oil and citrus fruit.

Dual counter-current chromatography (dual CCC) has been successfully applied to rapid sample preparation for the simultaneous determination of residual carbaryl, fenobucarb and methomyl in vegetable oil and citrus fruit. The citrus fruit samples were extracted with n-hexane solution containing stable isotopically labeled internal standards (methomyl-d3, fenobucarb-d3 and carbaryl-d9), and applied to dual CCC using a two-phase solvent system of n-hexane-acetonitrile to purify the carbamate pesticides from aliphatic sample matrix. The coiled column was rotated at 420 rpm, the lower mobile phase was introduced through the head toward the tail, and the upper mobile phase in the opposite direction. Due to the high partition efficiency of dual CCC, the lower phase fraction collected from 2 to 5 min after injection could be subjected to flow-injection tandem mass spectrometry directly after concentration. Repetitive sample injection can be performed at high reproducibility without a risk of contamination from the compounds retained in the column.

Carbamates↗
PubMed2006

How to achieve rapid separations in counter-current chromatography.

A new generation of high performance coil planet centrifuges is now making it possible to realize the enormous potential of liquid-liquid partition chromatography for the rapid and predictable scale up of separation processes. This paper uses a separation of flavonoids to demonstrate how rapid fractionations can be obtained at high flow rates with limited loss of resolution and with significant increase in throughput. Furthermore, it is shown that chromatograms at various flows can be modeled so that optimum conditions can be rapidly assessed.

Countercurrent Distribution↗
PubMed2006

Preparative isolation and purification of chemical constituents from the root of Polygonum multiflorum by high-speed counter-current chromatography.

High-speed counter-current chromatography methods, combined with solvent partition, were applied to the systematic separation and purification of chemical components from Chinese medicinal herb Polygonum multiflorum extract. The aim of this paper is summing up the rules of solvent system selection for diverse fractions of herbal extract, and establishing the systematic pattern to screen the bioactive constituents rapidly. Nine compounds including emodin, chrysophanol, rhein, 6-OH-emodin, emodin-8-beta-D-glucoside, polygonimitin B, 2,3,5,4'-tetrahydroxystilbene-2-beta-D-glucoside, gallic acid and an unknown glycoside, which differed in quantity and polarity remarkably, were obtained. The purities of them were all above 97% as determined by high-performance liquid chromatography (HPLC), and their structures were identified by 1H NMR and electrospray ionization mass spectrometry (ESI-MS). The results demonstrated that HSCCC is a speedy and efficient technique for systematic isolation of bioactive components from traditional medicinal herbs.

Anthraquinones↗
PubMed2006

Preparative isolation of four new and two known flavonoids from the leaf of Patrinia villosa Juss. by counter-current chromatography and evaluation of their anticancer activities in vitro.

A preparative counter-current chromatography (CCC) was used to isolate and separate chemical constituents from the leaf of Patrinia villosa, a famous traditional Chinese medicinal herb. Six flavonoids including two known and four novel compounds were successfully simultaneous purified by CCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (10: 13: 13: 10, v/v) by increasing the flow rate of the mobile phase from 1.0 ml/min to 2.0 ml/min after 110 min to bring out the late eluters. The separation produced total of 44.9 mg fraction I with 99.1% purity, 35.5 mg fraction II with 98.8% purity, 79.8 mg fraction III with 99.3% purity, 45.8 mg fraction IV with 98.8% purity, 39.8 mg fraction V with 98.6% purity and 9.6 mg fraction VI with 97.5% purity from 400 mg crude extract in one single isolation procedure and less than 10 h, and the obtained fractions were all analyzed by high performance liquid chromatography (HPLC). Their chemical structures were elucidated as (2S)-5,7,2',6'-tetrahydroxy-6,8-di (gamma,gamma-dimethylallyl) flavanone (1), (2S)-5,7,2',6'-tetrahydroxy-6-lavandulylated flavanone (2), (2S)-5,7,2',6'-tetrahydroxy-4'-lavandulylated flavanone (3), (2S)-5,2',6'-trihydroxy-2'',2''-dimethylpyrano [5'', 6'': 6, 7] flavanone (4), (2S, 3''S)-5,2',6'-trihydroxy-3''-gamma,gamma-dimethylallyl-2'',2''-dimethyl-3'',4''-dihydropyrano [5'', 6'': 6, 7] flavanone (5) and licoagrochalcone B (6), respectively, by spectrum methods including UV, IR, high resolution (HR)-electrospray ionization (ESI)-MS, 1-dimension (1D) and 2-dimension (2D) NMR techniques. Among them, compounds 2, 3, 4, and 5 were new compounds and discovered from nature for the first time. The recoveries of the six compounds were 91.2%, 91.4%, 92.1%, 90.5%, 90.3% and 89.7%, respectively, in CCC step. Subsequently, their anticancer activities were also examined to inhibit human cancer cells' growth including A549, BEL-7402, SGC-7901, MCF-7, HT-29, K562 and A498 cell lines by MTT method in vitro. The results indicated that the compounds 1, 2 and 3 exhibited high anticancer activities (IC50 < 7 microg/ml), especially to K562 cancer cell (IC50 < 3.1 microg/ml), and the compounds 4, 5 and 6 exhibited weaker inhibition effect (IC50 < 30 microg/ml).

Antineoplastic Agents, Phytogenic↗
PubMed2006

Preparative isolation of imperatorin, oxypeucedanin and isoimperatorin from traditional Chinese herb "bai zhi"Angelica dahurica (Fisch. ex Hoffm) Benth. et Hook using multidimensional high-speed counter-current chromatography.

Preparative high-speed counter-current chromatography (CCC) was successfully used for isolation and purification of imperatorin, oxypeucedanin and isoimperatorin from traditional Chinese herb "bai zhi"Angelica dahurica (Fisch. ex Hoffm) Benth. et Hook using multidimensional counter-current chromatography with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at volume ratios of 1:1:1:1 (v/v) and 5:5:4.5:5.5 (v/v), which had been selected by analytical high-speed counter-current chromatography (HSCCC). Using two preparative units of the CCC centrifuge, which are connected by a column switching valve, about a 300 mg amount of the crude extract was separated, yielding 19.9 mg of imperatorin, 8.6 mg of oxypeucedanin and 10.4 mg of isoimperatorin all at a high purity of over 98%.

Angelica↗
PubMed2006

Purification of salvianolic acid B from the crude extract of Salvia miltiorrhiza with hydrophilic organic/salt-containing aqueous two-phase system by counter-current chromatography.

Establishment of hydrophilic organic/salt-containing aqueous two-phase system and purification of salvianolic acid B from crude extract of S. miltiorrhiza by counter-current chromatography with said system were studied. Ethanol and n-propanol were selected to constitute biphasic systems with ammonia sulphate, sodium chloride and phosphate separately, and related system characteristics including phase diagrams, phase ratio, separation time were tested. The partition coefficient of crude salvianolic acid B was also tested in above systems and further finely adjusted by altering the constitution of phosphate in n-propanol/phosphate system. Salvianolic acid B was purified to 95.5% purity by counter-current chromatography in 36% (w/w) n-propanol/8% (w/w) phosphate system with the ratio between dipotassium hydrogen phosphate and sodium dihydrogen phosphate of 94:6. One hundred and eight milligrams of salvianolic acid B was purified from 285 mg crude extract with the recovery of 89%.

Benzofurans↗
PubMed2006

Application of high-speed counter-current chromatography coupled with high-performance liquid chromatography-diode array detection for the preparative isolation and purification of hyperoside from Hypericum perforatum with online purity monitoring.

Following preparative isolation and purification by high-speed counter-current chromatography (HSCCC), the collected fractions were generally analyzed by high-performance liquid chromatography (HPLC) to determine the relative purities of each fraction. Our paper reports for the first time a preparative isolation-purity detection hyphenated system: online coupling of HSCCC with high-performance liquid chromatography-diode array detection (HSCCC-HPLC-DAD). The introduction of online purity analysis in HSCCC has dramatically improved the efficiency of this technique by overcoming the drawbacks of post analysis in HSCCC isolation. The effluent from the outlet of HSCCC was splitted into two parts: one was collected, while the other was introduced directly into an HPLC-DAD system for purity analysis through a switch valve. Therefore, the purities of the obtained fractions from HSCCC were monitored, and fractions with high purities were collected. This strategy has been successfully demonstrated with the preparative isolation and purification of hyperoside from Hypericum perforatum (St. Jone's Wort); a model of TBE-300A HSCCC was used to isolate and separate hyperoside from H. perforatum with a two-phase solvent system composed of ethyl acetate-ethanol-water at the volume ratio of 5:1:5 (v/v) using online detection technique. The isolation was done in less than 3.5 h, and a total of 83.0-mg hyperoside at over 99.0% purity was yielded from 300 mg of the partially purified extract. This new strategy possesses general utility in the preparation of bioactive compounds from traditional Chinese medicine (TCM).

Chromatography, High Pressure Liquid↗
PubMed2006

Apolar chromatography on Sephadex LH-20 combined with high-speed counter-current chromatography. High yield strategy for structurally closely related analytes-Destruxin derivatives from Metarhizium anisopliae as a case study.

A novel high yield isolation procedure for lipophilic cyclic peptide derivatives is presented. Destruxin (dtx) A, B, D, E, and E-diol retrieval from Metarhizium anisopliae culture broth was achieved with a three-step purification protocol. After liquid-liquid extraction column chromatography over Sephadex LH-20 served as enrichment step. High-speed counter-current chromatography (HSCCC) was used for the final purification. Within the first chromatographic step dtx D and dtx E-diol were separated in purities exceeding 90%. The separation of dtx A, B, and E was achieved from an enriched Sephadex LH-20 fraction by a HSCCC protocol using light petroleum-ethyl acetate-methanol-water = 2:5:2:5 (v/v) as eluent system. These derivatives were obtained in purities above 98% and total yields exceeding 40%.

Ascomycota↗
PubMed2006

Large-scale separation of alkaloids from Corydalis decumbens by pH-zone-refining counter-current chromatography.

pH-zone-refining counter-current chromatography was successfully applied to the separation of alkaloids from a crude extract of Corydalis decumbens (Thunb.) Pers. using a multilayer coil planet centrifuge (CPC). The experiment was performed with a two-phase solvent system composed of methyl tert-butyl ether (MtBE)-acetonitrile-water (2:2:3, v/v) where triethylamine (5-10 mM) was added to the upper organic stationary phase as a retainer and hydrochloric acid (5-10 mM) to the aqueous mobile phase as an eluter. From 3.1 g of the crude extract, 495 mg protopine, 626 mg tetrahydropalmatine and 423 mg bicuculline were obtained each with a purity of over 93% as determined by high performance liquid chromatography. The structures of the isolated compounds were identified by electron ionization mass spectrometry (EI-MS), high-performance liquid chromatography (HPLC)-electrospray ionisation-mass spectrometry (ESI-MS) and 1H NMR.

Acetonitriles↗
PubMed2006

High-speed counter-current chromatography for the study of defense metabolites in wheat. Characterization of 5,6-O-methyl trans-aconitic acid.

High-speed counter-current chromatography (HSCCC) methods were developed for the study of induced defense metabolites in wheat (Triticum aestivum) against powdery mildew (Blumeria graminis f. sp. tritici). A single HSCCC purification step afforded extraction of mg-quantities of an induced compound with antifungal activity. Subsequent LC-MS and NMR analyses have led to the characterization of 5,6-O-methyl trans-aconitic acid, the first such report of this compound in a plant species. The inducible nature of aconitic acid was evidenced by comparing the metabolite profiles of leaf extracts from plants treated or not with soluble silicon and infected or not with powdery mildew. In a second step, dual-mode HSCCC was used to enhance the separation of other forms of aconitic acid in wheat. Based on these results, it was concluded that 5,6-O-methyl trans-aconitic acid plays an important role as a defense molecule in wheat plants and that HSCCC is a powerful separation method for purifying such compounds from complex plant-pathogen interactions.

Aconitic Acid↗
PubMed2006

Counter-current chromatography using hexane/surfactant-containing water solvent systems.

We developed a n-hexane/surfactant-containing water solvent system in counter-current chromatography (CCC) in order to separate hydrophobic compounds. By using the upper phase as the mobile phase, we have separated steroid samples. Retention times of steroids progesterone and delta4-androstene-3,17-dione increased slightly by increasing the concentration below the critical micellar concentration (CMC) of surfactant sodium 1-heptanesulfonate. However, the retention times increased drastically while the SHS concentrations were above the CMC. The partition of these two steroids in the two phases was significantly dependent on the interaction with micelles. Aromatic hydrocarbons were not retained by the lower phase no matter what the surfactant concentrations were. Their hydrophobic interaction with n-hexane greatly exceeded that with the micellar solution. The retention times of esters, however, were only slightly affected by the surfactant addition even above the CMC. The weaker interaction between esters and the micellar solution was probably due to their higher polarity. The micellar solvent systems provide an alternative way for hydrophobic sample separations in CCC, but the performance is limited.

Countercurrent Distribution↗
PubMed2006

A continuous, counter-current multi-column chromatographic process incorporating modifier gradients for ternary separations.

The existing literature of continuous chromatographic process indicates the scarcity of processes which allow the continuous separation of a ternary mixture and which also exploit the power of modifier gradients and counter-currency. A new process filling this gap is presented and analyzed using an equilibrium theory model and linear isotherms. The analysis leads to the explicit formulation of an operating region, where 100% purity and yield can be obtained. A normalized flow rate ratio is introduced, which allows an easy description and understanding of the process behavior. The gained insights are verified using a detailed simulation model, where the influence of changes in the normalized flow rate ratios on the unit performance is investigated.

Computer Simulation↗
PubMed2006

Theoretical study of multicomponent continuous countercurrent chromatography based on connected 4-zone units.

Continuous countercurrent or simulated moving bed (SMB) chromatography is a well-established separation technology. Conventional processes are based on four zones which fulfil distinct functions in order to split a feed into two fractions. Frequently there is an interest in isolating a target component out of a feed mixture containing more than two components. Modifications of the classical SMB process are required to solve this task. In the last years several concepts exploiting more than four zones have been suggested. To analyse these concepts the equilibrium theory has been frequently applied, neglecting all kinetic effects. It is the purpose of this paper to apply an equilibrium stage model in order to describe the performance of a combination of two or three 4-zone true moving bed units which are connected in series or integrated into 8- or 12-zone true moving bed units. The performance of such units is evaluated with respect to their potential to continuously separate ternary or quaternary mixtures. The analysis is based on the assumption of linear adsorption isotherms. An important aspect is the introduction of additional purge streams required for a successful operation of integrated 8- and 12-zone units.

Computer Simulation↗