<p> Recently, it has been shown that a decrease in activity of acetylcholinesterase (AChE) in AD patients is compensated by an increase in butyrylcholinesterase (BuChE) activity. Therefore, BuChE also becomes a significant target in the treatment of cognitive loss associated with Alzheimer&rsquo;s disease. While the majority of drug development so far has centered on AChE inhibitors in order to increase the acetylcholine level in AD patients, the development of specific and potent BuChE inhibitors have also begun to attract attention. We recently synthesized and assayed a library of bisthiophosphates as potential BuChE inhibitors. To evaluate if the analogs were selective for BuChE, their inhibitory properties against both BuChE and AChE were determined. </p><p>

Analytical methods of separation are the focus of this dissertation. Several of the studies are of a clinical nature and concern the effects of various medication and materials additives on low birth weight infants. In all cases, the chemicals under consideration are federally approved species, but must be reevaluated because of the underdevelopment of the infants. The first study investigates butylated hydroxy toluene (BHT), a common food and drug antioxidant, which is a component of the nutrition supplement administered to children. A high performance liquid chromatographic determination for the BHT and metabolites was required. Reverse phase chromatography was employed using photodiode array detection. This allowed for post-run optimization of detection wavelengths which was critical due to the limited sample size available. Sample preparation utilized solid phase extraction methodology to reduce the biological matrix. Results which highlight the differences between adult and infant samples are given. The second study incorporates element specific detection with a microwave induced plasma for gas chromatographic analysis to determine isothiazolinones in infant blood. This feasibility study illustrates the ability of the technique to discriminate the analytes from a complex matrix. Lysing of red blood cells was found to be necessary in order to quantitatively determine the analytes at the part per billion level necessary. The final clinical study exploits the features of photodiode array detection for liquid chromatography. A chromatographic peak is shown to contain two components and the source of the contaminant has been traced to drug infusion tubing. This peak has not been positively identified but spectral and retention characteristics suggest that it is a polymeric stabilizer used in the manufacture of polyvinylchloride tubing. Next, capillary isotachophoresis is employed to separate the conformers of calmodulin, a metallo-protein which undergoes changes in its tertiary structure as it binds up to four calcium ions. In isotachophoresis analytes travel with constant velocity in an electric field. Differences in electrophoretic mobilities allow analytes to migrate into discrete zones. Conductivity detection was used in this analysis. A description of the process and instrumentation is followed by a section of troubleshooting analysis. The separation of the calmodulin conformers is shown and experimental considerations for working with this and other metallo-proteins are discussed.