Novel approaches for the chromatographic and electrophoretic separation of molecules

Doctor of PhilosophyDepartment of ChemistryChristopher T. CulbertsonHigh-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are two well-established analytical separation techniques that are continuously being adapted for performing distinctive separations and analyses of multitudes of complex and/or unique samples. Since their introduction, these techniques have been pivotal in the discovery, analysis, and understanding of a variety of samples and still prove to be key analytical tools for biological investigation. Using these techniques, one can obtain a wide-range of valuable sample information from the hydrophobicity and molecular weights to size and charge distributions. Furthermore, these techniques allow for sample analysis, purification, and collection for additional sample analysis, such as mass spectrometry analysis. My doctoral dissertation encompasses the full scope of these two techniques and novel approaches for the investigation of distinct, relevant samples. Described herein is the fabrication of glass microfluidic devices used for CE and their diversity for numerous investigations. Chapter 2 shows that the resolution of the photomasks used in microchip fabrication does not alter the separation efficiency of the devices, as the separations remain diffusion-limited. Using an in-house built capillary electrophoresis system, wheat proteins were separated more than 25% faster than previously reported in literature, and the electropherograms used for sample varietal identification. The fabrication of a robust, portable CE system capable of performing biological analysis in microgravity and hypergravity environments is also discussed. The need for and features necessary to achieve a reliable, robust, automated system is further described in Chapter 4. Isolation and analysis of the pea aphid (Acyrthosiphon pisum) salivary secretions was completed for the first time using HPLC. By altering the aphid environment and the sample treatment parameters, sample concentrations were increased above the limit of detection. Coupled with mass spectrometry, identification of pea aphid salivary proteins such as exopeptidase, angiotensin converting enzyme, and Buchnera proteins has been achieved. Finally, a simplified contact conductivity detection system for the detection of jurkat cells was developed that surpasses current, complex optical systems. The experiments described in this dissertation demonstrate novel approaches for the preparation, separation, analysis, and identification of a wide variety of common, and uncommon, samples