Enantiomer separation by nonaqueous and aqueous capillary electrochromatography on cyclodextrin stationary phases
2001; Wiley; Volume: 22; Issue: 12 Linguagem: Inglês
10.1002/1522-2683(200107)22
ISSN1522-2683
AutoresDorothee Wistuba, Karin Cabrera, Volker Schurig,
Tópico(s)Innovative Microfluidic and Catalytic Techniques Innovation
ResumoNative β- and γ-cyclodextrin bound to silica (Chira Dex-beta and Chira Dex-gamma) were packed into capillaries and used for enantiomer separation by capillary electrochromatography (CEC) under aqueous and nonaqueous conditions. Negatively charged analytes (dansyl-amino acids) were resolved into their enantiomers by nonaqueous CEC (NA-CEC). The addition of a small amount of water to the nonaqueous mobile phase enhanced the enantioselectivity but increased the elution time. The choice of the background electrolyte (BGE) determined the direction of the electroosmotic flow (EOF). With 2-(N-morpholino) ethanesulfonic acid (MES) or triethylammonium acetate (TEAA) as BGE an inverse EOF (anodic EOF) was observed while with phosphate a cathodic EOF was found. The apparent pH (pH*), the concentration of the BGE, and the nature of the mobile phase strongly influenced the elution time, the theoretical plate number and the chiral separation factor of racemic analytes.
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