Electrophoresis chiral

GM Beck, SH Neau. A-carrageenan A novel chiral selector for capillary electrophoresis. Chirality 8 503-510, 1996. 

DK Lloyd, S Li, P Ryan. Investigation of enantioselective ligand—protein binding and displacement interactions using capillary electrophoresis. Chirality 6 230-238, 1994. 

Apryll M. Stalcup received her PhD in chemistry (1988) from Georgetown University in Washington, DC. After postdoctoral training at the University of Missouri-Rolla, she joined the Department of Chemistry at the University of Hawaii-Manoa in 1990 as an assistant professor. She moved to the Chemistry Department at the University of Cincinnati as an associate professor in 1996 and was promoted as a professor in 2002. Her research interests include liquid chromatography, capillary electrophoresis, chiral separations, and investigations of separation mechanisms. 

Hui, F. (2004) High Performance Liquid Chromatography and Capillary Electrophoresis Chiral Recognition Mechanisms Using Glycopeptide Macrocyclic Antibiotics as Selectors, Fenxi Huaxue 32, 964-968. 

M. M. Rogan, K. D. Altria, and D. M. Goodall, Enantioselective separations using capillary electrophoresis, Chirality 6-.25 (1994). 

F Wang, MG Khaledi. Non-aqueous capillary electrophoresis chiral separations with sulfated beta-cyclodextrins. J Chromatogr B 731 187-197, 1999. 

Evans C.E., Stalcup A.M., Comprehensive strategy for chiral separations using sulfated cyclodextrins in capillary electrophoresis. Chirality, 15, 709-723 (2003). 

Zhou L., Thompson R., Song S., Ellison D., Wyvratt J.M., A strategic approach to the development of capillary electrophoresis chiral methods for pharmaceutical basic compounds using sulfated cyclodextrins. J. Pharm. Biomed. Anal., 27, 541-553 (2002). 

Jiang C, Tong MY, Armstrong DW, Perera S, Bao Y, MacDonnell FM (2009) Enantiomeric separation of chiral ruthenium(II) complexes using capillary electrophoresis. Chirality 21 208-217... 

Wang F, Khaledi M (1998) Nonaqueous capillary electrophoresis chiral separations with quaternary ammonium P-cyclodextrin. J Chromatogr A 817 121-128... 

Francotte E, Cherkaoui S, Faupel M (1993) Separation of the enantiomers of some racemic nonsteroidal aromatase inhibitors and barbiturates by capillary electrophoresis. Chirality 5 516-526... 

Armstrong DW, Rundlett K, Chen J (1994) Evaluation of the macrocycUc antibiotic vancomycin as a chiral selector for capUlary electrophoresis. Chirality 6 496-509... 

Bergholdt BA, Lehmann SV (1998) High-speed separation of ormeloxifene enantiomers using sulfated P-cyclodextrin in capillary electrophoresis. Chirality 10 699-704... 

Capillary Electrophoresis. Capillary electrophoresis (ce) or capillary 2one electrophoresis (c2e), a relatively recent addition to the arsenal of analytical techniques (20,21), has also been demonstrated as a powerful chiral separation method. Its high resolution capabiUty and lower sample loading relative to hplc makes it ideal for the separation of minute amounts of components in complex biological mixtures (22,23). 

Catechin and epicatechin are two flavanols of the catechin family. They are enantiomers. The capillary zone electrophoresis (CE) methods with UV-detection were developed for quantitative determination of this flavanols in green tea extracts. For this purpose following conditions were varied mnning buffers, pH and concentration of chiral additive (P-cyclodextrin was chosen as a chiral selector). Borate buffers improve selectivity of separation because borate can make complexes with ortho-dihydroxy groups on the flavanoid nucleus. 

B. Chankvetadze, Capillary Electrophoresis in Chiral Analysis, Jolm Wiley Sons, New Yoi-k (1997). 

Recently, the separation of some milligram quantities of terbutaline by classical gel electrophoresis has been reported [194]. A sulfated cyclodextrin impregnated on the agarose gel was used as a chiral selector and the complete resolution was achieved in 5 h. Analogously, small amounts of enantiomers can be isolated using thin-layer... 

Library of Cyclic Oligopeptides as Additives to Background Electrolyte for Chiral Capillary Electrophoresis... 

Enantioresolution in capillary electrophoresis (CE) is typically achieved with the help of chiral additives dissolved in the background electrolyte. A number of low as well as high molecular weight compounds such as proteins, antibiotics, crown ethers, and cyclodextrins have already been tested and optimized. Since the mechanism of retention and resolution remains ambiguous, the selection of an additive best suited for the specific separation relies on the one-at-a-time testing of each individual compound, a tedious process at best. Obviously, the use of a mixed library of chiral additives combined with an efficient deconvolution strategy has the potential to accelerate this selection. 

Chiral additives have been shown to be very effective for chiral separations by capillary electrophoresis (CE) [4, 5]. Indeed, it may be argued that there has been considerably more research activity in chiral separations by CE than by EC methods since the introduction of the former technique. Chiral additives in CE have several advantages, some of which are highlighted in Table 11-2. 

CE is generally more suited to analytical separations than to preparative-scale separations. However, given the success of CE methods for chiral separations, it seems reasonable to explore the utility of preparative electrophoretic methods to chiral separations. Thus, the purpose of this work is to highlight some of the developments in the application of preparative electrophoresis to chiral separations. Both batch and continuous processes will be examined. 

In considering the applicability of preparative classical electrophoretic methods to chiral separations, it should be noted that practitioners in the art of classical electrophoresis have been particularly inventive in designing novel separation strategies. For instance, pH, ionic strength and density gradients have all been used. Isoelectric focusing and isotachophoresis are well-established separation modes in classical electrophoresis and are also being implemented in CE separations [7, 8]. These trends are also reflected in the preparative electrophoretic approaches discussed here. 

Stalcup aiid co-workers [14] adapted this method to a continuous elution mini-prep electrophoresis apparatus shown in Fig. 11-3. In this apparatus, the end of the electrophoretic gel is continuously washed with elution buffer. The eluent can then be monitored using an HPLC detector (Fig. 11-4) and sent to a fraction collector where the purified enantiomers, as well as the chiral additive, may be recovered. In this system, the gel configuration was approximately 100 mm x 7 mm, and was aircooled. The number of theoretical plates obtained for 0.5 mg of piperoxan with this gel was approximately 200. A larger, water-cooled gel was able to handle 15 mg of... 

Ward, T. J., Chiral media for capillary electrophoresis, Anal. Chem., 66, 634A, 1994. 

High performance capillary electrophoresis in its current form is a new technique. Its feasibility has been proven by the analysis and separation of small ions, drugs, chiral molecules, polymers, and biopolymers.93 We are learning more every day about the small tricks of the trade of the technique, and the efficiency and reproducibility of the methods are improving. 

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