Zhao, Hong
(2006)
PARTITIONING AND MOLECULAR RECOGNITION IN TEFLON AF / FC-72 AND DETERMINATION OF BARBITURATES WITH CAPILLARY ELECTROPHORESIS.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The unique nature of fluorocarbon solvents makes them significant in selective extraction. We studied noncovalent intermolecular associations in fluorous media (fluorous solvents/polymers), and receptor enhanced-extraction of 3-hydroxypyridine with a fluorous solvent, FC-72, and a fluorous polymer, Teflon AF 2400. The association through hydrogen bonding and electrostatic interactions between fluorinated carboxylic acids and 3-hydroxypyridine improves the extraction of 3-hydroxypyridine into FC-72 and the films prepared from Teflon AF 2400. The association is found to be substantially stronger in FC-72 than in chloroform; however weaker in the fluorous films due to the specific properties of the polymer and sorption of solvents in the films. Dimensionally stable and chemically inert fluorous polymer films have advantages in fluorous separations. Films of Teflon AF 2400 were cast from solution. Transport measurements on a series of solutes with different polarity and functional groups reveal that the selectivity of the films with and without a perfluoropolyether plasticizer. The films favor the transport of fluorinated solutes in comparison to the hydrogen-containing control. Transport rates are dependent on the solvent making up the source and receiving phases. Various solvents, including organic solvents and the nonvolatile perfluoropolyether plasticizer, were investigated and compared.To study the selectivity of extraction and membrane transport, an important part of the work is analysis of mixtures of solutes. Capillary electrophoresis (CE) is a powerful analytical technique for separation of diverse samples. For increased sensitivity in CE, we investigated the optimal stacking conditions for separation of barbiturates and analogs with capillary zone electrophoresis (CZE), and micellar electrokinetic chromatography (MEKC). To achieve stacking for all the analytes that have a wide distribution of affinity for the SDS micelles in MEKC, high pH sample matrices have been used to ionize the analytes, thus decreasing their affinity for the SDS micelles, and resulting stacking similar as that in CZE. Both normal stacking and transient ITP stacking mechanism are involved, depending on the sample matrix.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
30 March 2006 |
| Date Type: |
Completion |
| Defense Date: |
22 August 2005 |
| Approval Date: |
30 March 2006 |
| Submission Date: |
8 September 2005 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
barbiturate; capillary electrophoresis; fluorous; MEKC; molecular recognition; Partition; polymer; stacking; Teflon AF |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-09082005-144715/, etd-09082005-144715 |
| Date Deposited: |
10 Nov 2011 20:01 |
| Last Modified: |
15 Nov 2016 13:50 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/9340 |
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[feed]](/images/feed-icon-32x32.png){kind=icon}