Separation capillary zone electrophoresis

Capillary electrophoretic separation Capillary zone electrophoresis... 

Capillary zone electrophoresis provides effective separations of any charged species, including inorganic anions and cations, organic acids and amines, and large biomolecules such as proteins. For example, CZE has been used to separate a mixture of 36 inorganic and organic ions in less than 3 minutes.Neutral species, of course, cannot be separated. 

Diet soft drinks contain appreciable quantities of aspartame, benzoic acid, and caffeine. What is the expected order of elution for these compounds in a capillary zone electrophoresis separation using a pH 9.4 buffer solution, given that aspartame has pJC values of 2.964 and 7.37, benzoic acid s pfQ is 4.2, and the pfQ for caffeine is less than 0. 

Biomolecule Separations. Advances in chemical separation techniques such as capillary zone electrophoresis (cze) and sedimentation field flow fractionation (sfff) allow for the isolation of nanogram quantities of amino acids and proteins, as weU as the characterization of large biomolecules (63—68) (see Biopolymers, analytical techniques). The two aforementioned techniques, as weU as chromatography and centrifugation, ate all based upon the differential migration of materials. Trends in the area of separations are toward the manipulation of smaller sample volumes, more rapid purification and analysis of materials, higher resolution of complex mixtures, milder conditions, and higher recovery (69). 

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. 

Electrodriven Separation Techniques encompass a wide range of analytical procedures based on several distinct physical and chemical principles, usually acting together to perform the requh ed separation. Example of electrophoretic-based techniques includes capillary zone electrophoresis (CZE), capillary isotachophoresis (CITP), and capillary gel electrophoresis (CGE) (45-47). Some other electrodriven separation techniques are based not only on electrophoretic principles but rather on chromatographic principles as well. Examples of the latter are micellar... 

Figure 9.5 The generic setup for two-dimensional liquid chromatography-capillary zone electrophoresis as used by Jorgenson s group. The LC separation was performed in hours, while the CZE runs were on a time scale of seconds.

Figure 9.10 Three-dimensional representation of the data volume of a tryptic digest of ovalbumin. Series of planar slices through the data volume produce stacks of disks in order to show peaks. Reprinted from Analytical Chemistry, 67, A. W. Moore Jr and J. W. Jorgenson, Comprehensive three-dimensional separation of peptides using size exclusion chromatogra-phy/reversed phase liquid chromatography/optically gated capillary zone electrophoresis, pp. 3456-3463, copyright 1995, with permission from the American Chemical Society.

A. V. Lemmo and J. W. Jorgenson, Two-dimensional protein separation by mictocolumn size-exclusion chromatography-capillary zone electrophoresis , 7. Chromatogr. 633 213-220(1993). 

A. W. Moore, Jr and J. W. Jorgenson, Comprehensive three-dimensional separation of peptides using size exclusion chromatography/reversed phase liquid chromatography/ optically gated capillary zone electrophoresis . Anal. Chem. 67 3456-3463 (1995). 

J. H. Beattie, R. Self and M. P. Richards, The use of solid phase concenti ators for online pre-concentration of metallothionein prior to isofom separation by capillary zone electrophoresis , Electrophoresis 16 322-328 (1995). 

Yuan, K. et al., Application of capillary zone electrophoresis in the separation and determination of the curcuminoids in urine, J. Pharm. Biomed. Anal, 38, 133, 2005. 

Capillary electrophoresis (CE) has several unique advantages compared to HPLC, snch as higher efficiency dne to non-parabolic fronting, shorter analytical time, prodnction of no or much smaller amounts of organic solvents, and lower cost for capillary zone electrophoresis (CZE) and fused-silica capillary techniques. However, in CZE, the most popular separation mode for CE, the analytes are separated on the basis of differences in charge and molecular sizes, and therefore neutral compounds snch as carotenoids do not migrate and all co-elute with the electro-osmotic flow. 

Ichiyanagi, T. et al., Complete assignment of bilberry (Vaccinium myrtillus L.) anthocyanins separated by capillary zone electrophoresis, Chem. Pharm. Bull, 52, 226, 2004. 

Very recently, HPLC with fluorescence detection was recommended for improving detection sensitivities of betalains. " While this technique may be worthwhile for betaxanthin analyses, its use for betacyanins cannot be recommended. Although this technique represents a worthwhile approach requiring low amounts of solvent and sample and generally characterized by a high separation efhciency, only one study dealt with the use of capillary zone electrophoresis for betalain analyses. ... 

Capillary electrophoresis is increasingly used in food analysis due to its separation performance combined with the short time of analysis. - CapiUary electrophoresis recently applied to colorant measurements includes technical variants such as capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography. ... 

Masar, M., Kaniansky, D., and Madajova, V., Separation of synthetic food colourants by capillary zone electrophoresis in a hydrodynamically closed separation compartment, J. Chromatogr. A, 724, 327, 1996. 

Owing to their high separation efficiency, the potential for using micellar electro-kinetic chromatography and capillary zone electrophoresis (CZE) ... 

Fujiwara, S. and Honda, S., Effect of addition of organic solvent on the separation of positional isomers in high-voltage capillary zone electrophoresis, Anal. Chem., 59, 487, 1987. 

Wu, S. and Dovichi, N. J., Capillary zone electrophoresis separation and laser-induced fluorescence detection of zeptomole quantities of fluorescein thiohy-dantoin derivatives of amino acids, Talanta, 39, 173, 1992. 

Grossman, R D., Wilson, K. J., Petrie, G., and Lauer, H. H., Effect of buffer pH and peptide composition on the selectivity of peptide separations by capillary zone electrophoresis, Anal. Biochem., 173, 265, 1988. 

Terabe, S., Yashima, T., Tanaka, N., and Araki, M., Separation of oxygen isotopic benzoic acids by capillary zone electrophoresis based on isotope effects on the dissociation of the carboxyl group, Anal. Chem., 60,1673, 1988. 

Kilar, F. and Fanali, S., Separation of tryptophan-derivative enantiomers with iron-free human serum transferrin by capillary zone electrophoresis, Electrophoresis, 16, 1510, 1995. 

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