Studies to increase separation selectivity in capillary electrophoretic chiral separations using B-cyclodextrin-containing polymers /
A mathematical model that describes the separation selectivity for chiral compounds in capillary electrophoresis predicts that selectivity will increase for Type 11 and /// separations, when the ionic mobility of the enantiomer:chiral resolving agent complexes is decreased by, for example, bonding t...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=741965111&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A mathematical model that describes the separation selectivity for chiral compounds in capillary electrophoresis predicts that selectivity will increase for Type 11 and /// separations, when the ionic mobility of the enantiomer:chiral resolving agent complexes is decreased by, for example, bonding the chiral resolving agent to a polymer, or entrapping the chiral resolving agent in the pores of a crosslinked gel or a linear polymer network. In this work, 0-cyclodextrin (0-CD) was derivatized to yield polyallylcarbamoyl-o-CD (ac-o-CD), mono-6-0-allyl-o-CD (MAC), and mono-6-0allylcarbamoyl-o-CD, which then were copolymerized with acrylamide and vinyl acetate. Crosslinked polyacrylamide gels were synthesized by polymerizing ac-O-CD in the presence of acrylamide and bisacrylamide. Though these gels exhibit higher selectivity values for the separation of the enantiomers of dansyl-D,L-leucine, they were irreproducible, their performance varied from batch to batch of ac-O-CD, and their lifetimes were short. Because of this, crosslinked polyacrylamide gels were abandoned in favor of linear polymers, which are more easy to manipulate and last longer. Pure MAC was synthesized as chiral gel monomer to ensure reproducibility. The complexation constants of homatropine with O-CD were determined in the MACacrylamide copolymers and compared to an analog system where O-CD was not bonded to a polymer. D,L-homatropine was used as test compound since its separation with @-CD was known to be a Type // separation. MAC was copolymerized with acrylamide to yield MAC:acrylamide copolymers (MW 52,000). The ionic mobility of the homatropine enantiomer:O-CD complexes was decreased by 30-40% from 3.5 and 3.7 x 1 0-5 (in the non- bonded O-CD system) to 2.3 and 2.6 x 10-5 CM2 Ns (in the MAC:acrylamide copolymer system). But the decrease in mobility, represented by p (the ratio of the new and original mobilities), was not the same for both enantiomers: for the D-homatropine, p was equal to 0.64, while for the L-enantiomer, p was equal to 0.70. In addition, the values of the complexation constants decreased by 10% in the MAC system. Because of these factors, larger selectivity values are only observed in the MAC system when the migration order of the enantiomers is reversed. |
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| Item Description: | Vita. "Major Subject: Chemistry". In title, Greek symbol for Beta is used. |
| Physical Description: | xiv, 109 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |