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Journal of Liquid Chromatography & Related Technologies 01/2007; 30(9–10):1475-1488. · 0.71 Impact Factor
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ABSTRACT: In order to find a versatile high speed counter-current chromatography solvent system that can be used as a general prefractionation system for most alkaloids, the crude extracts of five Chinese traditional medicinal herbs, Cortex phellodendri, Semen strychni, green tea, Sophora flavescens ait, and Datura mete L. were resolved. All separations were performed only with a two-phase system composed of CHCl3-CH3OH-water (4:3:2). The water had different acidities controlled by adding NaH2PO4 or HCl to each sample. The fractionated components were identified by thin-layer chromatography, which confirmed this solvent system was versatile and very useful for the separation of alkaloids.
Journal of Chromatography 09/2001; 927(1-2):91-6. · 4.53 Impact Factor
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ABSTRACT: A system of m (12.5% PEG8000): m (25% K2HPO4) = 1:1 was used to separate two kinds of standard proteins, glycoprotein in Morchella esculenta (L.) and glycoprotein in Lycium barbarum (L.), the upper phase was used as stationary phase, and the lower phase was used as mobile phase. The revolution speed was 500 r/min and the flow rate was 60 mL/h. In comparing with high performance liquid chromatography, cross-axis counter current chromatography can increase load capacity without loss of resolution. The advantage of this method was verified, indicating that cross-axis counter current chromatography was a useful method for biopolymer separation.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 04/2001; 19(2):188-90.
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ABSTRACT: High-speed counter-current chromatography (HSCCC) was applied to the isolation and purification of lutein from microalgae. Analytical HSCCC was used for the preliminary selection of a suitable solvent system composed of n-hexane-ethanol-water (4:3:1, v/v). Using the above solvent system, preparative HSCCC was successfully performed yielding lutein at 98% purity from 200 mg of the crude extract in a one-step separation.
Journal of Chromatography 02/2001; 905(1-2):151-5. · 4.53 Impact Factor
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ABSTRACT: Supercritical fluid extraction of tea catechins including epigallocatechin-3-O-gallate (EGCG) and epicatechin-3-O-gallate (ECG) from Cratoxylum prunifolium Dyer was performed. The optimization of parameters was carried out using an analytical-scale supercritical fluid extraction (SFE) system designed in our laboratory. Then the extraction was scaled up by 100 times using a preparative SFE system under a set of optimized conditions of 40 degrees C, 25 MPa and modified CO2 with 80% ethanol aqueous solution. The combined yield of EGCG and ECG reached about 1 mg per 1 g of tea leaves where the solubility was near 1.4 x 10(-4) mass fraction of CO2 fluid. EGCG and ECG of high purity (>98%) were obtained from the crude preparative extract by high-speed counter-current chromatography.
Journal of Chromatography 11/2000; 898(1):75-81. · 4.53 Impact Factor
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ABSTRACT: High-speed counter-current chromatography (HSCCC) was used for the separation and purification of 10-deacetylbaccatin III from the needle extract of Chinese yew (Taxus chinensis). The crude needle extract (500 mg/5 ml) was first separated with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (2:5:2:5, v/v) and the partially purified fraction was again purified with a different solvent system composed of n-hexane-chloroform-methanol-water (5:25:34:20, v/v). HPLC analysis of the final fraction showed that the purity of 10-deacetylbaccatin (20 mg) was over 98%. The chemical structure was confirmed by fast atom bombardment MS and 1H NMR.
Journal of Chromatography 08/1998; 813(2):397-401. · 4.53 Impact Factor
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ABSTRACT: A multidimensional counter-current chromatographic system was set up for the first time with two sets of high-speed counter-current chromatography instruments. This system was successfully applied to the preparative separation of isorhamnetin, kaempferol and quercetin from crude flavone aglycones of Ginkgo biloba L. and Hippophae rhamnoides L. with a two-phase solvent system composed of chloroform-methanol-water (4:3:2, v/v/v).
Journal of Chromatography 05/1998; 803(1-2):298-301. · 4.53 Impact Factor
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ABSTRACT: High-speed countercurrent chromatography (HSCCC) was applied to the semi-preparative separation of taxol and its analogs, such as cephalomannine and 7-epi-10-deacetyltaxol from the extract of the bark of Taxus yunnannesis. The experiments were performed with a quaternary two-phase solvent system composed of n-hexane-thyl acetate-ethanol-water through two steps. In the first step, the four components were separated into two groups at a volume ratio of 1:1:1:1 and, in the second step, two components in each group were separated at different volume ratios of 3:3:2:3 or 4:4:3:4. The present method also allows consecutive injections with reproducible results. HPLC analysis showed that the purity of the four components obtained from a partially purified sample, containing taxol at 10%, ranged from 85 to 99%. The results indicated that HSCCC can be effectively used for the semi-preparative separation and purification of taxol and its analogs.
Preparative Biochemistry & Biotechnology 03/1998; 28(1):79-87. · 0.47 Impact Factor
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ABSTRACT: Epigallocatechin gallate (EGCG) was hydrolyzed at various concentrations of tannase under pH 6.0 at 35 degrees C, and the reaction mixtures were separated by high-speed counter-current chromatography with a two-phase solvent system composed of hexane-ethyl acetate-water (1:13:20). The best results were obtained when 2 mg/ml of the enzyme buffer solution was added to 0.3 M EGCG buffers at a rate of 0.1 ml/min. Using 10 mg of the enzyme, 342 mg of epigallocatechin were obtained at a purity of 99.1%.
Journal of Chromatography 01/1995; 687(1):174-7. · 4.53 Impact Factor
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ABSTRACT: Horizontal flow-through coil planet centrifuge (CPC) and high-performance liquid chromatography (HPLC) techniques were used for separation of polar compounds from a crude ethanol extract of Oxytropis ochrocephala Bunge, a poisonous legume plant widely distributed in northwestern China. The performance of these two chromatographic methods was compared in terms of column efficiency, peak resolution, separation time, sample loading capacity, etc. The results indicated that two polar compounds in the crude extract were equally well separated by these two methods. HPLC gave comparable peak resolution in shorter separation time while its sample loading capacity was limited to the mg range. The CPC method required a long separation time, but yielded a higher purity of fractions with a much greater capacity.
Journal of Chromatography 02/1991; 538(1):219-25. · 4.53 Impact Factor
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ABSTRACT: A preparative capability of the present cross-axis synchronous flow-through coil planet centrifuge was demonstrated with 0.5 cm I.D. multilayer coils. Results of the model studies with short coils indicated that the optimal separations are obtained at low revolutional speeds of 100-200 rpm in both central and lateral coil positions. Preparative separations were successfully performed on 2.5-10 g quantities of test samples in a pair of multilayer coils connected in series with a total capacity of 2.5 l. The sample loading capacity will be scaled up in several folds by increasing the column width.
Journal of Chromatography 12/1988; 455:151-62. · 4.53 Impact Factor
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ABSTRACT: The cross-axis synchronous flow-through coil planet centrifuge with a 20-cm revolutional radius and a total capacity of 1600 ml was successfully applied to preparative counter-current chromatography of various biological samples, which include sea buckthorn extract, steroid reaction mixture, indole plant hormones, and dinitrophenylamino acids. The present system offers advantages of stable balance of the centrifuge, a large column capacity, and high resolution.
Journal of Chromatography 12/1988; 454:185-93. · 4.53 Impact Factor
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ABSTRACT: Using a new cross-axis synchronous flow-through coil planet centrifuge with a 20-cm revolutional radius, the retention of the stationary phase for nine solvent systems was studied with short coils mounted at two different locations on three holders with 5-, 15- and 25-cm hub diameters. Coils mounted 10 cm to the left of the center of a holder produced a much improved retention of most of the solvent systems compared with the same coils mounted at the center of the holder. In the lateral coil position the retention was found to be affected by the direction of the planetary motion and the head-tail elution mode. This phenomenon may be attributed to the effect of the lateral force field acting asymmetrically between the upper and lower halves of the coil.
Journal of Chromatography 10/1988; 449(1):135-51. · 4.53 Impact Factor
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ABSTRACT: A commercial model of the analytical high-speed counter-current chromatography instrument was used for separation of flavonoids from a crude ethanol extract of dried fruits of sea buckthorn (Hippophae rhamnoides). Using a two-phase solvent system of chloroform-methanol-water (4:3:2), a five-fold increase in flow-rate of the mobile phase from 60 to 300 ml/h resulted in a rapid separation of five components in less than 15 min without significant loss in peak resolution. Major flavonoid component, isorhamnetin, was identified in its pure state by mass spectrometric analysis.
Journal of Chromatography 08/1988; 445(1):199-206. · 4.53 Impact Factor
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Journal of Chromatography 07/1988; 442:455-8. · 4.53 Impact Factor
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ABSTRACT: 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.
Journal of Chromatography 04/1988; 437(1):121-9. · 4.53 Impact Factor
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ABSTRACT: Counter-current chromatography is a new liquid-liquid partition chromatography without using solid support. Recently, the technique has been remarkably improved in both partition efficiency and separation time. In this paper the capability of this high-speed counter-current chromatography was demonstrated on separation of two sets of samples obtained from medicinal herbs: a synthetic mixture of 3'-hydroxygenkwanin, luteolin and apigenin was separated on a two-phase solvent system composed of chloroform-methanol-water (4:3:2, v/v/v) and a crude ethanol extract from Anisodus tangulicus (Maxin) Pasch on chloroform-0.07 M sodium phosphate (pH 6.4) (1:1, v/v). In the light of chromatograms obtained from these samples, advantages of high-speed counter-current chromatography over other chromatographic methods were discussed in terms of partition efficiency, peak resolution, separation time, sample loading capacity, etc.
Journal of Chromatography 02/1988; 435(1):159-66. · 4.53 Impact Factor
