Doctor of Philosophy (PhD)
Protein biomarkers in bodily fluids can lead to an indication of the onset of a disease. Due to low abundance of the biomarker at early stages of the disease and other protein interferences, detection may be challenging. Therefore, in order to achieve more selective protein separations, the development of a novel stationary phase has been investigated. Moreover, novel methods to apply polysaccharides as stationary phases were developed for protein separations as well as chiral separations. The initial discussions in this dissertation commences with the use of novel zwitterionic lysine-based molecular micelles as a coating for open tubular capillary electrochromatography (OT-CEC) for protein separations. Poly-å-sodium-undecanoyl lysinate (poly-å-SUK) was evaluated as a stationary phase by varying polymer concentration, voltage, and temperature in the separation of six acidic (myoglobulin, albumin, â-lactoglobulin A, â-lactoglobulin B, á-lactalbumin, deoxyribonuclease I) and four basic (á-chymotrypsinogen A, lysozyme, cytochrome c, and ribonuclease A) proteins. Additionally, NaCl concentration was assessed for enhancement of the separation due to increased interactions from polymer swelling. Nearly all protein peaks were baseline resolved. In addition, a separation of proteins in a human serum sample was evaluated under optimized acidic and basic conditions. Furthermore, a separation of proteins in a human serum sample was also evaluated under optimized acidic and basic conditions. This dissertation also addresses chiral separations using polysaccharides derivatives (cellulose acetate (CA), cellulose acetate phthalate (CAP), and cellulose acetate butyrate (CAB)) for OT-CEC. These hydrophobic polymers were each dissolved in a room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium acetate and deposited into capillaries. Four chiral analytes (thiopental, sotalol, labetalol, and ephedrine) were evaluated using the coated capillaries. The system was optimized using pH, polymer concentration, voltage, and temperature studies. Examination of results indicated baseline resolution for thiopental using each polysaccharide, while only partial separation was achieved for sotalol, labetalol, and ephedrine. Lastly, protein separations were evaluated using polysaccharides as coatings for OT-CEC. Basic proteins, mentioned earlier, were investigated using CA, CAP, and CAB. CA had the fastest analysis time, and it was further investigated in this study. Polymer concentration, temperature, and voltage studies were conducted to determine optimized conditions. In addition, proteins were evaluated using CA nanofibers. Nanofibers were coated at various times onto the capillary wall for the separation of basic proteins.
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Moore, Jr., Leonard, "Development of innovative stationary phases for chiral and protein separations in open tubular capillary electrochromatography" (2012). LSU Doctoral Dissertations. 3757.
Warner, Isiah M.