Enantiomer separations by preparative electrophoresis : theory and practice /
A secondary chemical equilibrium-based model has been developed to describe the IEF separations of ampholytic enantiomers. This model predicts the magnitude of the []pI difference that can be created between the ampholytic enantiomers in the presence of a neutral chiral resolving agent. The DpI valu...
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
2000.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=728415801&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A secondary chemical equilibrium-based model has been developed to describe the IEF separations of ampholytic enantiomers. This model predicts the magnitude of the []pI difference that can be created between the ampholytic enantiomers in the presence of a neutral chiral resolving agent. The DpI value depends on the concentration of the resolving agent and the complexation constants of the enantiomers. The validity of the model has been tested with hydroxypropyl-β-cyclodextrin as a resolving agent and Dns-Phe as a probe. Capillary IEF enantiomer separations have been achieved first using carrier ampholytes, then binary serine-propionic acid buffers. The binary serine-propionic acid medium was applied for the preparative-scale IEF separation of the enantiomers of Dns-Phe using a continuous, free-flow electrophoretic unit. A production rate of 1.3 mg/h per enantiomer has been achieved, along with a product purity of 100%. The preparative IEF separation of the enantiomers of Dns-Phe was achieved in a multicompartment electrolyzer with a series of isoelectric membranes. In this unit, the buffer components are covalently attached to membranes, and the separation medium consists only of hydroxypropyl-β-cyclodextrin and deionized water. A production rate of 0.1 mg/h has been achieved with a product purity of 100%. Zone electrophoresis was the method of choice for the separation of the enantiomers of a weak base, terbutaline with a permanently charged resolving agent: heptakis-6-sulfato-β-cyclodextrin. Analytical-scale electrophoretic separations showed, that the two enantiomers migrate with equal mobilities, but in the opposite directions when the concentration of the resolving agent is 1 to 2 mM. This condition leads to maximal resolution and is advantageous for preparative-scale separations. Using the continuous, free-flow electrophoretic unit, the enantiomers of terbutaline were separated with a production rate of 0.1 mg/h, a recovery rate of 95% and product purity of 100%. |
|---|---|
| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xii, 116 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 107-111). |