Design, synthesis, and evaluation of selectors and stationary phases for improved liquid chromatographic separations
Welch, Christopher J.
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/21787
Description
Title
Design, synthesis, and evaluation of selectors and stationary phases for improved liquid chromatographic separations
Author(s)
Welch, Christopher J.
Issue Date
1992
Doctoral Committee Chair(s)
Pirkle, William H.
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Analytical
Language
eng
Abstract
In this study a diverse array of research projects are presented, all having to do with the development of selectors and stationary phases for improved liquid chromatographic separations. Apart from the introductory material, two main topics are addressed: (1) the role of non-specific adsorption in chromatographic separations, and (2) the synthesis of selectors designed for recognition of particular analyte molecules.
In the introductory part of the thesis the use of 1,3,5-tri-t-butylbenzene as an improved void volume marker for several chiral stationary phases (CSPs) is described, as is a thermodynamic study investigating the role of solvation in a well characterized chiral recognition system.
The role of non-specific adsorption in chromatographic separations has been addressed for both the analyte and the stationary phase. A study of the effect of superfluous remote polar functionality on chiral recognition shows that polar groups not required in the chiral recognition process can have a deleterious effect on enantiomer separations by increasing retention and sometimes reducing enantioselectivity. The preparation of CSPs in which nonessential interaction sites have been eliminated leads to CSPs showing reduced retention and increased enantioselectivity.
"An improved CSP designed for the non-steroidal anti-inflammatory drug, naproxen, is described in-five different studies. A ""reciprocal"" approach was used in this study, (S)-naproxen being immobilized to produce a CSP which was used to screen potential naproxen selectors. This study revealed several key features important for the enantioselective recognition of naproxen, which were incorporated inio a novel selector and CSP displaying a high degree of enantioselectivity for underivatized naproxen. The underivatized enantiomers of a number of related drugs such as ibuprofen, ketoprofen, etc. are easily separable using this CSP."
Finally, the rational design of an improved selector and stationary phase for the carbon cluster buckminsterfullerene (C$\sb{60}$) is described. A tripodal selector containing three $\pi$-acidic aromatic rings for simultaneous multipoint interaction with the spherical analyte molecule was immobilized on silica to afford a stationary phase displaying a high degree of retention for buckminsterfullerene, and a large separation factor for separation of the C$\sb{60}$/C$\sb{70}$ mixture.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
