register

Company
Catalogues
About Us
HPLC
Columns
Materials
Accessories
Narrow Bore
Coltrak400
CE/CEC
Accessories
Capillaries
Capital Brands
Optimal
Inertpak
Spherisil
Type-C Silica
Contact Us

 

These macrocyclic carbohydrate compounds are widely used as buffer additives to obtain chiral separations in CE. However, the can also be used to adjust the selectivity in non-chiral applications. There are three naturally occurring forms, a, b and g which have 6, 7 and 8 glucose units respectively. The structure of b-cyclodextrin is shown below. The hydroxyl units on the top of the cyclodextrin are chrially positioned and have different interactions with solute enantiomers when they are included into the cyclodextrin cavities. The hydroxyl groups can be chemically derivatised to give a range of neutral and ionic derivatives which give different chiral separations and are more water soluble that the naturally occurring forms

Neutral cyclodextrin derivatives most frequently used in CE dimethyl-cyclodextrin trimethyl-cyclodextrin hydroxypropyl-cyclodextrin Most commonly used ionic forms cyclodextrin sulphonic acid carboxymethyl-cyclodextrin amino-cyclodextrin We can supply a wide range of high purity cyclodextrins for chiral CE separations.

Structure of Beta Cyclodextrin

The shape of cyclodextrins is often represented as a cone shaped cavity as shown.

 

Separation Mechanism for Chiral CE The cyclodextrins form inclusion complexes with the different enantiomers which results in a chiral separation being obtained. A range of different sized and chemically modified cyclodextrins are used to obtain the required chiral separation. See diagram below:

The different forms of chiral analytes interact with the cyclodextrins to different extents and a separation is achieved.

Order here