Capillary electrophoresis separation factor

Table 10,5 Factors affecting capillary electrophoresis separations...

The heating effect is the limiting factor for all electrophoretic separations. When heat is dissipated rapidly, as in capillary electrophoresis, rapid, high resolution separations are possible. For electrophoretic separations the higher the separating driving force, ie, the electric field strength, the better the resolution. This means that if a way to separate faster can be found, it should also be a more effective separation. This is the opposite of most other separation techniques. 

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... 

In E. Coli bacterial lysates, the proteome (i.e., the full array of proteins produced) was analyzed by isoelectric focusing and mass spectrometry.97 A comparison of capillary electrophoretic separation and slab gel separation of a recombinant monoclonal antibody demonstrated that the precision, robustness, speed, and ease-of-use of CE were superior.98 Seventy-five proteins from the yeast ribosome were analyzed and identified by capillary electrophoresis coupled with MS/MS tandem mass spectrometry.99 Heavy-chain C-terminal variants of the anti-tumor necrosis factor antibody DE7 have been separated on capillary isoelectric focusing.100 Isoforms differing by about 0.1 pi units represented antibodies with 0,1 or 2 C-terminal lysines. 

Schure (1999) has studied the effect of multidimensional dilution for column-based separations that incorporate chromatography, capillary electrophoresis (CE), and FFF. In all of these cases, the dilution factors are multiplicative this gives the direct result that the limit of detection for MDC is... 

Fan et al. [106] developed a high performance capillary electrophoresis method for the analysis of primaquine and its trifluoroacetyl derivative. The method is based on the mode of capillary-zone electrophoresis in the Bio-Rad HPE-100 capillary electrophoresis system effects of some factors in the electrophoretic conditions on the separation of primaquine and trifluoroacetyl primaquine were studied. Methyl ephedrine was used as the internal standard and the detection was carried out at 210 nm. A linear relationship was obtained between the ratio of peak area of sample and internal standard and corresponding concentration of sample. The relative standard deviations of migration time and the ratio of peak area of within-day and between-day for replicate injections were <0.6% and 5.0%, respectively. 

Factors Affecting Ionic Migration. Effect of Temperature. pH and Ionic Strength. Electro-osmosis. Supporting Medium. Detection of Separated Components. Applications of Traditional Zone Electrophoresis. High-performance Capillary Electrophoresis. Capillary Electrochromatography. Applications of Capillary El ectrochromatography. ... 

Anions and uncharged analytes tend to spend more time in the buffered solution and as a result their movement relates to this. While these are useful generalizations, various factors contribute to the migration order of the analytes. These include the anionic or cationic nature of the surfactant, the influence of electroendosmosis, the properties of the buffer, the contributions of electrostatic versus hydrophobic interactions and the electrophoretic mobility of the native analyte. In addition, organic modifiers, e.g. methanol, acetonitrile and tetrahydrofuran are used to enhance separations and these increase the affinity of the more hydrophobic analytes for the liquid rather than the micellar phase. The effect of chirality of the analyte on its interaction with the micelles is utilized to separate enantiomers that either are already present in a sample or have been chemically produced. Such pre-capillary derivatization has been used to produce chiral amino acids for capillary electrophoresis. An alternative approach to chiral separations is the incorporation of additives such as cyclodextrins in the buffer solution. 

Capillary electrochromatography (CEC) is a miniaturized separation technique that combines aspects of both interactive chromatography and capillary electrophoresis. In this chapter, the theory of CEC and the factors affecting separation such as the stationary phase and mobile phase parameters have been discussed. The chapter focuses on the types and preparation of columns for CEC and describes the progress made in the development of open-tubular, particle-packed, and monolithic columns. The detection techniques in CEC such as the traditional UV detection and improvements made in coupling with more sensitive detectors such as mass spectrometry are also described. The chapter provides a summary of some applications of CEC in the analysis of pharmaceuticals and biotechnology products. 

IE Valko, HAH Billiet, J Frank, KChAM Luyben. Factors affecting the separation of mandelic acid enantiomers by capillary electrophoresis. Chromatographia 38 730-736, 1994. 

PD Ferguson, DM Goodall, JS Loran. Systematic approach to links between separations in capillary electrophoresis and liquid chromatography. IV. Application of binding constant-retention factor relationship to the separation of... 

Variation of ion mobility with pH is only part of the story with regard to separation by capillary electrophoresis - the other major factor is electro-osmotic flow (EOF). 

In capillary electrophoresis, components of a mixture are separated according to two main factors electrophoretic mobility and electro-osmotic flow. These terms apply to ions, molecules or micelles. 

Successful detection of S3P-labeled molecules separated by capillary electrophoresis using the above detection schemes, in which a sensor was positioned external to the separation channel, was made possible by several factors. These included (1) the large energy associated with 0 decay of S3P (1.7 MeV), (2) the high sensitivity and small size of commercially available semiconductor detectors, (3) the availability of efficient solid scintillator materials and sensitive photomultiplier tubes, (4) the short lengths of fused silica (capillary wall thickness) and aqueous electrolyte through which the radiation must pass before striking the detector, and (5) the relatively short half-life of S3P (14.3 days). 

There are several good reasons why CE has not captured the lion s share of small-molecule separations. High-performance liquid chromatography (HPLC) has a 23-year head start over capillary electrophoresis, and most of the problems have been worked out. HPLC is rugged, sensitive, scales up to preparative and commercial modes, and scales down to the capillary format. Poorly developed CE methods by ill-trained chromatographers are another contributing factor to the slow acceptance of CE in the world of small molecules. 

Factors affecting ionic migration. F.ffecl of temperature. pH ami ionic strength. Elcciroosmosis. Supporting medium. Detection oF.separated components. Applications of tradional zone electrophoresis. High per- formance capillary electrophoresis. 

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