Chiral capillary electrochromatography

Zheng, J., and Shamsi, S. A. (2003). Combination of chiral capillary electrochromatography with electrospray ionization mass spectrometry method development and assay of warfarin enantiomers in human plasma. Anal. Chem. 75, 6295—6305. 

Quaglia M, De Loienzi E, Sulitzky C, Massolini G, Sellergren B. Surface initiated molecularly imprinted polymer films a new approach in chiral capillary electrochromatography. Analyst 2001 126 1495-1498. 

The most frequently applied CE techniques for chiral separations are capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC) and chiral capillary electrochromatography (CEC). Two strategies are generally adopted for the enantiomer resolution in these electrophoretic techniques ... 

This limitation applies even more so to chiral capillary electrochromatography (CEC). This technique [27] is essentially LC in a fused silica capillary using an electric field rather than a pressure drop to drive the flow. As such the separations may be achieved by chiral derivatisation, by use of a CMPA or a CSP... 

Capillary electrochromatography-mass spectrometry (CE-MS), 4 641 Capillary electrodes, 14 27 Capillary electrophoresis (CE), 4 602-603, 631-633 6 385 9 751-752 antibody based columns with, 6 402 chiral additives, 6 77-79 applications, 4 641 basic principles, 4 606-609 detectors, 4 634-635 for DNA analysis, 4 636-637 flow profiles generated, 4 608 instrumentation, 4 633 as microfluidic assay technique,... 

In a different approach, Lin et al. have used particles derived from a ground MI-bulk polymer and mixed with a polyacryl amide gel for chiral separation. Using a polymer imprinted with L-phenylalanine, D-phenylalanine could be separated from the template with a separation factor of 1.45 [35]. Although the combination of MIP with capillary electrochromatography is still not widely used, the ability to separate enantiomers in nanoliter samples promises interesting developments for the future. 

Wikstrom, H. et ah. Immobilisation and evaluation of a vancomycin chiral stationary phase for capillary electrochromatography, J. Chromatogr. A, 869, 395, 2000. 

Schmid, M.G, et al., Enantioseparation of dipeptides by capillary electrochromatography on a teicoplanin aglycone chiral stationary phase, J. Chromatogr. A., 990, 83, 2003. 

Mangelings, D., Tanret, I., Matthijs, N., Maftouh, M., Massart, D.L., Vander Heyden, Y. Separation strategy for acidic chiral pharmaceuticals with capillary electrochromatography on polysaccharide stationary phases. Electrophoresis 2005, 26, 818-832. 

Scriba, G. K. E. (2003). Pharmaceutical and biomedical applications of chiral capillary electrophoresis and capillary electrochromatography an update. Electrophoresis 24(15), 2409-2421. 

Lim, J. M., Nakagama, T, Uchiyama, K., and Hobo, T. (1997). Temperature effect on chiral recognition of some amino acids with molecularly imprinted polymer filled capillary electrochromatography. Biomed. Chromatogr. 11, 298-302. 

Karlsson, C., Wikstrom, H., Armstrong, D. W, and Owens, P. K. (2000). Enantioselective reversed-phase and non-aqueous capillary electrochromatography using a teicoplanin chiral stationary phase.. Chromatogr. A 897(1-2, 3), 349-363. 

Lammerhofer, M., Tobler, E., Zarbl, E., Lindner, W., Svec, E, and Frechet, J. M. J. (2003). Macroporous monolithic chiral stationary phases for capillary electrochromatography new chiral monomer derived from cinchona alkaloid with enhanced enantioselectivity. Electrophoresis 24, 2986-2999. 

Kamande, M. W., Zhu, X., Kapnissi-Christodoulou, C., and Warner, 1. M. (2004). Chiral separations using a polypeptide and polymeric dipeptide surfactant polyelectrolyte multilayer coating in open-tubular capillary electrochromatography. Anal. Chem. 76, 6681—6692. 

DK Lloyd, S Li, P Ryan. Protein chiral selectors in free-solution capillary electrophoresis and packed-capillary electrochromatography. J Chromatogr A 694 285-296, 1995. 

Y. Gong and H. K. Lee, Application of Cyclam-Capped (5-Cyclodextrin-Bonded Silica Particles as a Chiral Stationary Phase in Capillary Electrochromatography for Enantiomeric Separations, Anal. Chem. 2003, 75,... 

M. W. Kamande, X. Zhu, C. Kapnissi-Christodoulou, and 1. M. Warner, Chiral Separations Using a Polypeptide and Polymeric Dipeptide Surfactant Polyelectrolyte Multilayer Coating in Open-Tubular Capillary Electrochromatography, Anal. Chem. 2004, 76, 6681. 

The use of antibiotic-based CSPs has been reported in capillary electrochromatography (CEC) for chiral resolution [60]. Teicoplanin CSP covalently bonded to silica gel was used to resolve the enantiomers of tryptophan and dinitrobenzoyl leucine by CEC [61]. Good levels of enantioselectivity were obtained with optimized separations. Vancomycin covalently bonded to silica gel was also evaluated in CEC for the chiral resolution of thalidomide and jS-adrenergic blocking agents under all the three mobile phase modes. The... 

In spite of the high speed and efficiency of capillary electrochromatography, the Pirkle-type CSPs could not be used frequently for chiral resolution purposes. Only a few reports are available on this issue. Cavender et al. [167] and Wolf et al. 

FIGURE 16 Effect of temperature on the chiral resolution of DL-phenylalanine on CSP prepared by imprinted L-phenylalanine molecule hy capillary electrochromatography using acetonitrile-acetic acid (95 5, v/v). Imprinted polymers were prepared at ( ) 60°C, ( ) 40°C, and (O) 4°C. (From Ref. 91.)... 

In addition to high-performance liquid chromatography (HPLC), the chiral resolution using CMPAs was also carried out by supercritical fluid chromatography (SFC) [91] and capillary electrochromatography (CEC) [92-98]. Salvador et al. [91] used dimethylated /1-cyclodextrin as the mobile phase additive on porous graphite carbon as the solid phase for the chiral resolution of tofizopam, warfarin, a benzoxazine derivative, lorazepam, flurbiprofen, temazepam, chlorthalidone, and methyl phehydantoin by SFC. The authors also studied the effect of the concentration of dimethylated /1-cyclodextrin, the concentration of the mobile phase, the nature of polar modifiers, outlet pressure, and the column temperature on the chiral resolution. 

Olsson and Blomberg [141] enantioseparated omeprazole and its metabolite 5-hydroxyomeprazole using open tubular capillary electrochromatography with immobilized avidin as chiral selector. The separation was performed with open tubular capillary electrochromatography. The protein avidin was used as the chiral selector. Avidin was immobilized by a Schiffs base type of reaction where the protein was via glutral-dehyde covalently bonded to the amino-modified wall of a fused-silica capillary, 50 /an i.d. Both racemates were baseline resolved. Resolution... 

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