Date of Award
Doctor of Philosophy (PhD)
Isiah M. Warner
Chirality is a characteristic of many synthetic and biological organic compounds. This property is particularly true in the pharmaceutical industry where a large number of drugs are marketed as racemates. One method used to monitor optical purity is capillary electrophoresis (CE). Chiral separation using CE is achieved by use of an immobilized chiral phase or through a chiral selector mobile phase additive. It is demonstrated and determined that chiral polymeric surfactants are more suitable for chiral separation in electrokinetic capillary chromatography (EKC) than conventional micelles. Polymeric surfactants eliminate the dynamic equilibrium that occurs in normal micelles, are more stable, rigid, have no critical micelle concentration (CMC), and can tolerate higher organic modifier content. The research presented in this dissertation generally embodies the synthesis, characterization, and application of polymeric surfactants. Specifically, a nonionic glucopyranoside and anionic Valine and Phenylalanine are examined as surfactant headgroups. All headgroups are coupled to an undecylenyl hydrocarbon tail before polymerization by gamma-irradiation. After completion of synthesis, the surfactant and/or polymeric surfactant is characterized using techniques such as elemental analysis, mass spectroscopy, nuclear magnetic resonance (NMR), optical rotation, light scattering, fluorescence spectroscopy, and analytical ultracentrilugation. From the characterization techniques, information including product identification, confirmation and purity, as well as polymer properties, such as size and microenvironment, were obtained. Applications involved using poly(undecyl-beta-glucopyranoside) (PUG) as a transient capillary coating to separate seven tricyclic antidepressant drugs in a modified capillary zone electrophoretic (CZE) mode. Poly(sodium-N-undecyl-L-valinate) is examined as an approach for developing a universal laboratory technique and procedure as well as for gaining insights into polymeric surfactant properties and characteristics. The latter is accomplished by conducting a polymerization concentration study. The use of EKC, fluorescence, and NMR revealed the differences in polymer enantioselectivity, size, shape, and dispersity relative to polymerization concentration. Phenylalanine monomer and dipeptide polymeric surfactants are used in EKC to examine their potential as pseudostationary phases. This study probes the possibility of enhanced enantioselectivity of binaphthyl atropisomers and benzodiazepines by increased hydrophobicity, steric, and pi-pi interactions.
Harrell, Crystal Williams, "Synthesis, Characterization, and Applications of Chiral Polymeric Surfactants in Micellar Capillary Electrophoresis." (1999). LSU Historical Dissertations and Theses. 6991.