Direct chiral separations capillary electrophoresis

Li, S., and Lloyd, D. K. (1993). Direct chiral separations by capillary electrophoresis using capillaries packed with an alpha(l)-acid glycoprotein chiral stationary phase. Anal. Chem. 65,... 

Chiral separation of drng molecules and of their precursors, in the case of synthesis of enantiomerically pure drugs, is one of the important application areas of HPLC in pharmaceutical analysis. Besides HPLC, capillary electrophoresis (CE) is another technique of choice for chiral separations. Chapter 18 provides an overview of the different modes (e.g., direct and indirect ones) of obtaining a chiral separation in HPLC and CE. The direct approaches, i.e., those where the compound of interest is not derivatized prior to separation, are discussed in more detail since they are cnrrently the most frequently used techniques. These approaches require the use of the so-called chiral selectors to enable enantioselective recognition and enantiomeric separation. Many different molecnles have been nsed as chiral selectors, both in HPLC and CE. They can be classified into three different groups, based on their... 

Capillary electrophoresis (CE) provides a valid alternative to HPLC methods for chiral separations. The direct resolution of racemates requires only an enantiomerically pure additive (chiral selector) to be dissolved in the running buffer. The experimental conditions affecting the separations and an overview of practical applications have been compiled <1999ELP2605>. 

Capillary electrophoresis and its most popular hybrid technique - capillary electrochromatography - are complementary to HPLC, offering rapid analysis, low consumption of sample and solvents, and usually a higher efficiency of separation (due to a larger number of theoretical plates). Similar to HPLC, enantioseparation with the use of electrophoretic methods can be conducted by direct (chiral phase... 

The increased need for stereoselective analyses has induced a tremendous development of analytical techniques resolving enantiomers. Among these techniques, liquid chromatography, and more recently capillary electrophoresis (CE), are recognized as methods of choice for the chiral separation of pharmaceutical compounds. Chiral discrimination by CE is generally achieved with the direct separation method where the chiral selector is simply added to the background electrolyte (BGE). 

Wan H, Andersson PE, Engstrom P, Blomberg LG (1995) Direct and indirect chiral separation of amino acids by capillary electrophoresis. J Chromatogr A 704 179-193 Varesio E, Gauvrit JY, Longeray R, Lanteri P, Veuthey J-L (1997).Central composite design in the chiral analysis of amphetamines by capillary electrophoresis. Electrophoresis 18 931-936... 

The most sensitive enantioselective separation technique is capillary zone electrophoresis. Here, the detectors utilized are not sensitive enough to be able to detect the enantiomers. In the case of sensors, amperometric biosensors have been found to be most sensitive.264 A better enantioselectivity was found for potentiometric, enantioselective membrane electrodes because a direct interaction between the chiral selector and enantiomer occurred.282 285... 

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