Enantioseparation of Aminoglutethimide by High-speed Countercurrent Chromatography Using Carboxymethly-β-cyclodextrin as Chiral Selector

Enantioseparation of aminoglutethimide was performed by high-speed counter-current chromatography with a two-phase system composed of ethyl acetate： methanol： water = 10： 1： 9. The lower phase contained 20 mmol/L of carboxymethly-β-cyclodextrin as chiral selector. The enantiomers were separated in 1.2 h and identified by chiral HPLC. This method was very efficient for the chiral preparative separation.

High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported. The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate, and the result mixture was separated using the two phase system composed of n-butanol/water = 1/1 （v/v）. The sizes of SWNTs separated were observed by scanning electron microscopy. The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

A novel long-chain acyl-derivative of epigallocatechin-3-O-gallate prepared and purified from green tea polyphenols

Lipophilic tea polyphenols (LTP) were prepared by catalytic esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long chain acyl derivative of epigallocatechin 3 o gallate (EGCG) was first isolated from purification of LTP by high speed countercurrent chromatography (HSCCC) using a solvent system composed of n hexane ethyl acetate methanol water (1:1:1:1, v/v). The molecular structure of the acyl derivative, Epigallocatechin 3 O gallate 4′ O hexadecanate , was elucidated by means of elemental analysis, IR, 1H NMR and MS spectra.

Recent Advances on Chiral Mobile Phase Additives: A Critical Review

Chirality is one of the fundamental attributes of nature, which exists in different or even completely opposite metabolic,toxicological and pharmacological properties in organisms. Consequently, obtaining enantiomerically pure drugs or optically active intermediates is highly desired in many fields like medicine, food and biochemistry. Thereby, it also promoted the development of various enantiomer selective separation techniques. Among the many chiral separation methods, chiral mobile phase additives(CMPAs) are widely used in various chromatographic techniques due to their simple operation,good versatility and low price. There have been a number of reviews on the research progress of CMPAs in last 2 decades,but they only reviewed the application of CMPAs in one specific chromatographic technique. Therefore, to provide a more comprehensive illustration of CMPAs in separation technology, their applications in high-performance liquid chromatography, capillary electrophoresis, countercurrent chromatography, nano-liquid chromatography were summarized and their advantages and disadvantages were briefly introduced in this critical review. The application of molecular simulation in the study of chiral separation mechanism was briefly summarized. We expect that it will provide researchers with the latest developments in this field and potential inspirations.

Purification of Puerarin from Pueraria lobata by FCPC versus HSCCC Using Small-volume Columns

Objective To develop an efficient method for separating and purifying puerarin from the roots of Pueraria lobata.Methods Separation by fast centrifugal partition chromatography（FCPC）was processed with a biphasic solvent system composed of ethyl acetate-n-butanol-water（2：1：3）.The separation conditions were determined as follows：sample loading of 10 mg,flow rate of 2 mL/min,rotation speed of 2200 r/min,ascending mode,and detection wavelength of 254 nm.High speed countercurrent chromatography（HSCCC）was used as a comparative method with the rotation speed of 800 r/min,flow rate of 2.0 mL/min,and sample loading of 10 mg in tail-to-head mode.Results Puerarin was obtained by FCPC with a resolution of 0.90 and a purity above 99%,while a resolution below 0.50 and a purity below 90%by HSCCC.Compared with HSCCC,FCPC has the advantages with higher purity and better resolution.Conclusion FCPC is a powerful method to separate and purify puerarin.

Isolation and Purification of a Novel Long-chain Acyl Catechin from Lipophilic Tea Polyphenols

Lipophilic tea polyphenols (LTP) was prepared by esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-chain acyl catechin was isolated and purified from LTP by high-speed countercurrent chromatography (HSCCC). Its molecular structure was elucidated as epigallocatechin-3-O-gallate-4'-O-hexadecanate by elemental analysis, IR, MS and H-1 NMR spectra.