Cyclodextrin-Mediated Chiral Separations - Chiral Separations by Capillary Electrophoresis - page 47

3 Cyclodextrin-Mediated

Chiral Separations

Gerald Gübitz and Martin G. Schmid

CONTENTS
3.1 Introduction ................................................................................................... 47
3.2 Use of Native CDs and Neutral CD Derivatives ........................................... 52
3.3 Use of Charged Cyclodextrin Derivatives..................................................... 53
3.3.1 Negatively Charged CD Derivatives................................................ 54
3.3.2 Positively Charged CD Derivatives ................................................. 54
3.3.3 Amphoteric CD Derivatives ............................................................ 57
3.4 Polymerized CDs .......................................................................................... 58
3.5 Dual Selector Systems................................................................................... 58
3.5.1 Dual CD Systems............................................................................. 58
3.5.2 CDs and Carbohydrates ................................................................... 58
3.5.3 CDs and Surfactants ........................................................................ 60
3.5.4 CDs and Ion-Pairing Reagents......................................................... 60
3.5.5 CDs and Crown Ethers .................................................................... 60
3.5.6 CDs and Macrocyclic Antibiotics .................................................... 61
3.5.7 Inclusion Complexation and Ligand-Exchange ............................... 61
3.6 Capillary Electrochromatography................................................................. 62
3.6.1 Open-Tubular CEC .......................................................................... 62
3.6.2 Packed CEC (P-CEC) ...................................................................... 63
3.6.3 Monolithic Phases............................................................................ 63
3.6.3.1 Silica-Based Monoliths .................................................... 63
3.6.3.2 Polymer-Based Monoliths ................................................ 65
3.7 Microl uid Devices........................................................................................ 66
3.8 Nonaqueous Medium .................................................................................... 67
3.9 Miscellaneous ............................................................................................... 68
References ................................................................................................................ 71

3.1 INTRODUCTION
Cyclodextrins (CDs) represent the most frequently used chiral selectors in electro-
migration techniques. CDs are oligosaccharides composed by different glucose units
connected to each other through

α -(1,4)-glucosidic bonds. They can be obtained by

enzymatic treatment of starch. α -CD consists of six, β -CD of seven, and γ -CD of

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