Capillary zone

Capillary Zone Electrophoresis The simplest form of capillary electrophoresis is capillary zone electrophoresis (CZE). In CZE the capillary tube is filled with a buffer solution and, after loading the sample, the ends of the capillary tube are placed in reservoirs containing additional buffer solution. Under normal conditions, the end of the capillary containing the sample is the anode, and solutes migrate toward... 

Capillary zone electrophoresis also can be accomplished without an electroosmotic flow by coating the capillary s walls with a nonionic reagent. In the absence of electroosmotic flow only cations migrate from the anode to the cathode. Anions elute into the source reservoir while neutral species remain stationary. 

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. 

The last set of experiments provides examples of the application of capillary electrophoresis. These experiments encompass a variety of different types of samples and include examples of capillary zone electrophoresis and micellar electrokinetic chromatography. 

Conte, E. D. Barry, E. E. Rubinstein, H. Determination of Caffeine in Beverages by Capillary Zone Electrophoresis, ... 

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. 

CE. (sometimes CZE), capillary electrophoresis (or capillary zone electrophoresis)... 

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). 

DETERMINATION OF POLYPHENOLIC ENANTIOMERS IN GREEN TEA EXTRACT BY CAPILLARY ZONE ELECTROPHORESIS... 

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 9.6 Surfer-generated chromatoeletropherogram of fluorescamine-labeled tryptic digest of ovalbumin. Reprinted from Analytical Chemistry, 62, M. M. Bushey and J. W. Jorgenson, Automated instrumentation for comprehensive two-dimensional high-performance liquid chromatography/capillary zone electrophoresis, pp 978-984, copyright 1990, with permission from the American Chemical Society.

ONLINE REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY-CAPILLARY ZONE ELECTROPHORESIS - MASS SPECTROMETRY... 

Figure 9.12 Schematic diagram of the silica sheath electrospray needle used to interface capillary zone electi ophoresis with a mass spectrometer.

S. Palmarsdottir and L. E. Edholm, Enhancement of selectivity and concentration sensitivity in capillary zone electrophoresis by on-line coupling with column liquid chromatography and utilizing a double stacking procedure allowing for microliter injections , 7. Chromatogr. 693 131-143 (1995). 

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, Rapid comprehensive two-dimensional separations of peptides via RPLC-optically gated capillary zone electiophoresis . Anal. Chem. 67 3448-3455 (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). 

E. J. Cole and R. T. Kennedy, Seleaive preconcenti ation for capillary zone electrophoresis using protein G immunoaffinity capillary chi omatography . Electrophoresis 16 549-556(1995). 

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