Capillary gel

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... 

Rill, RL Liu, Y Van Winkle, DH Locke, BR, Pluronic Copolymer Liquid Crystals Unique, Replaceable Media for Capillary Gel Electrophoresis, Journal of Chromatography A817, 287, 1998. 

Rill, RL Ramey, BA Van Winkle, DH Locke, BR, Capillary Gel Electrophoresis of Nucleic Acids in Pluronic F127 Copolymer Liquid Crystals, Chromatographia Supplement I, Vol 49, S65, 1999. 

Yiu, Y Locke, BR Van Winkle, DH Rill, RL, Optimizing Capillary Gel Electrophoretic Separations of Oligonucleotides in Liquid Crystalline Pluronic F127, Journal of Chromatography A817, 367, 1998. 

CE was recently used for anthocyanin analysis because of its excellent resolution. This technique has different modes capillary zone electrophoresis (CZE), capillary gel electrophoresis (CGE), micellar electrokinetic chromatography (MEKC), capillary electrochromatography (CEC), capillary isoelectric focusing (CIEE), and capillary isotachophoresis (CITP)."° CZE is the most popular method for anthocyanin... 

A variety of formats and options for different types of applications are possible in CE, such as micellar electrokinetic chromatography (MEKC), isotachophoresis (ITP), and capillary gel electrophoresis (CGE). The main applications for CE concern biochemical applications, but CE can also be useful in pesticide methods. The main problem with CE for residue analysis of small molecules has been the low sensitivity of detection in the narrow capillary used in the separation. With the development of extended detection pathlengths and special optics, absorbance detection can give reasonably low detection limits in clean samples. However, complex samples can be very difficult to analyze using capillary electrophoresis/ultraviolet detection (CE/UV). CE with laser-induced fluorescence detection can provide an extraordinarily low LOQ, but the analytes must be fluorescent with excitation peaks at common laser wavelengths for this approach to work. Derivatization of the analytes with appropriate fluorescent labels may be possible, as is done in biochemical applications, but pesticide analysis has not been such an important application to utilize such an approach. 

In the previously described electrophoretic methods, the capillary was filled with electrolytes only. Another mode of operation in capillary electrophoresis involves filling the capillary with gel or viscous polymer solutions. If desired, a column can be packed with particles and equipped with a frit.68 This mode of analysis has been favorably used for the size determination of biologically important polymers, such as DNA, proteins, and polysaccharides. The most frequently used polymers in capillary gel electrophoresis are cross-linked or linear polyacrylamide,69 cellulose derivatives,70-75 agarose,76 78 and polyethylene glycols. 

Figure 17 SDS-capillary gel electrophoresis of protein standards. Separation conditions 27 cm x 50 pm i.d. uncoated capillary 888 V/cm gel eCAP 200. (From Bene-dek, K. and Guttman, A., ]. Chromatogr., 680, 375, 1994. With permission.)...

Guttman, A. and Schwartz, H. E., Artifacts related to sample introduction in capillary gel electrophoresis affecting separation performance and quantitation, Anal. Chem., 34, 2279, 1995. 

Guttman, A., Separation of DNA by capillary gel electrophoresis, in Handbook of Capillary Electrophoresis, Landers, J. R, Ed., CRC Press, Boca Raton, FL, 1994, chap. 6. 

Guttman, A. and Pritchett, T., Capillary gel electrophoresis separation of high-mannose type oligosaccharides derivatized by l-aminopyrene-3,6,8-trisul-fonic acid, Electrophoresis, 16, 1906, 1995. 

Resolution in capillary gel electrophoresis of DNA sequencing was shown to be directly proportional to the product of the number of bases and the relative peak distance, i.e., to the mean separation of peaks.43 Reformulation of the treatment of the capacity factor has been used to simplify and clarify the interpretation of the separation factor in electrophoresis.44 Peak... 

Dittman, M. M. and Rozing, G. R, High-sensitivity separations of sodium dodecyl sulfate-protein complexes with capillary gel electrophoresis, LC-GC, 17(2), 132, 1999. 

Schmidt, T., Friehs, K., Schleef, M., Voss, C., and Hasche, E., Quantitative analysis of plasmid forms by agarose and capillary gel electrophoresis, Anal. Biochem., 274, 235, 1999. 

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