Capillary electrophoresis high-speed separations with

There is much interest in high-efficiency- and high-speed separation media for liquid chromatography. The plate numbers available in practice have been in the range of 10,000-30,000 in HPLC for 20 years or so, but these are low compared to well over 100,000 theoretical plates in capillary gas chromatography or in capillary electrophoresis. This is caused by the limitation in the use of small-sized particles for HPLC, where a particle-packed column is commonly used under a pressure-drop of up to 40 MPa. An increase in column efficiency by using small particles, which is the approach taken in the past, is accompanied by an increase in the pressure-drop, as expected from Eqns. 5.2 and 5.3, below. Eqns. 5.1-3 describe the efficiency (plate height) and flow resistance of a column packed with particles [1-3], where N stands for the... 

Volgger, D., Zemann, A. J., Bonn, G. K., and Antal, M. J., High-speed separation of carboxylic acids by co-electroosmotic capillary electrophoresis with direct and indirect UV detection, J. Chromatogr. A, 758, 263-276, 1997. 

Capillary electrophoresis has also been combined with other analytical methods like mass spectrometry, NMR, Raman, and infrared spectroscopy in order to combine the separation speed, high resolving power and minimum sample consumption of capillary electrophoresis with the selectivity and structural information provided by the other techniques [6]. 

C.S. Effenhauser, A. Manz, and M. Widmer, Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights. Anal. Chem. 65, 2637-2642 (1993). 

A further improvement of the more traditional slab gel analysis is the use of high-performance capillary electrophoresis (HPCE), which combines the separation power of high-performance liquid chromatography (HPLC) with the selectivity and speed of conventional gel electrophoresis. However, as HPCE separations are often performed using fused silica capillaries the positively charged histone molecules... 

Finally, when RPC methods are used in preparative studies with peptides, the opportunity routinely exists for subsequent analysis of the recovered fractions by a variety of analytical methods including high-speed RP-HPLC, HP-IEX, HP-HILIC, or HP-IMAC, zonal or micellar electrokinetic high-performance capillary electrophoresis (HP-CZE and MECK-CZE), capillary electrochromatography (CEC), or capillary isotachophoresis. The combination of the RPC information, drawn from the In k versus i > plots, with the data derived from on-line spectroscopic detection thus readily provides a comprehensive opportunity to assess the purity of an isolated peptide, many of the physicochemical features of the interaction, as well as a means to optimize the resolution in the RPC separation. 

Another format of chromatography which has been performed on electrophoresis chips is micellar electrokinetic capillary chromatography (MECC). This technique represents a very powerful extension of CE for the separation of both neutral species and ionic compounds, and has been originally developed by Terabe et al. [76]. Transfer of MECC to CE microchips has been first demonstrated by Moore et al. [77]. The experimental procedure used is identical to high speed CE, apart from the fact that a MECC buffer with 50 mM SDS and 10% methanol was used. Again three coumarin dyes were used as a model sample. Separation was achieved within a few minutes. At low applied field strengths (< 400 V/cm), the reproducibility was found to be excellent (below 1 %). 

Capillary electrophoresis (CE) is becoming a popular analytical tool for determining dmgs because of its simplicity, high speed, and high efficiency. The present review studies different modes of CE used in the determination and chiral separation of barbiturates, as well as current developments in sample preparation for barbiturates in biological fluids. The comparison of different modes of CE with other separation approaches is also discussed. 

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