Capital HPLC

TYPE III Diacel ChiralStationary Phases

TYPE III Diacel ChiralStationary Phases

These are inclusion type chiral stationary phases, in which the ‘host’ (the chiral stationary phase)
includes partially or completely a ‘guest’ (the solute) molecule. For an enantiomeric resolution too
occur, there must be a difference in the stability of the inclusion complexes formed for each
isomer of the solute.

Synthetic Polymers

Chiral synthetic polymers are designed to mimic or improve upon the success of natural polymers.
The two phases available from us, consist of an optically active polymethacrylate (see diagram
below) coated onto a 10mm wide pore silica. Chirality is derived only from helicity by inclusion of
all or part of the solute into a cavity.

The Structure of CHIRALPAK OT and OP

Solutes must possess an aromatic group, near or at the chiral centre, for an enantiomeric separation
to occur. These phases are excellent for separating compounds containing an axis of dissymmetry.
These phases have to be used within fairly strict guidelines, typically hexane/2-propanol, and users
are stongly recommended to consult the manufacturers literature. The phases are suitable for
preparative separations.


Crown Ethers

Crown ethers, at present only one phase is commercial available, CROWNPAK CR. It contains a 18-crown-6
type chiral crown ether as a chiral selector. Chiral recognition is achieved when a complex is formed with
an ammonium ion, from the analyte. For an enantiomeric separation to occur, the solute must have a primary
amino group at or near its chiral centre, such as in amino acids and aminoalcohols.
To date, twenty five amino acids have been separated in short analysis times (typically under 10 minutes), the
one exception is proline which is unresolved. For the CROWNPAK CR(+) column the D-amino acid always
elutes first.

The mobile phase used is aqueous perchloric acid at pH 1.0 to 2.0, at low temperatures (25oC to 0oC). The lower
the pH and temperature, the longer the solute is retained, and the better the separation. Preparative columns are
available.

Chiralpak OP and OT, Crownpak CR(+) Ordering Information

Description

Type

Dimensions

Cat.No.

Price/£

CHIRALPAKOP(+)(10mm)

column

250x4.6

9P1125

page17-18

 

guardcolumn

50x4.6

9P1105

page17-18

         

CHIRALPAKOT(+)(10mm)

column

250x4.6

9T1125

page17-18

 

guardcolumn

50x4.6

9T1105

page17-18

         

CROWNPAKCR(+) (5mm)

column

150x4.6

9R5115

page17-18

 

guardcolumn

10x4.6

9R5101

page17-18

         

 

 

 

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