UBC Theses and Dissertations
Determination of on-capillary pH and proton and hydroxide mobility in capillary electrophoresis Duso, Angela B.
The primary aim of this work is the measurement of on-capillary pH within the field of capillary electrophoresis. The first part of this thesis presents an investigation into the properties of the pH junction formed through a multi-electrolyte system within the capillary. For 1-unit pH differences, the pH character of a sample zone, sandwiched between zones of higher or lower pH was preserved, although the pH junctions themselves were observed to move. For 2-unit pH differences, an increase in time spent on the capillary, along with movement of the dye molecules being used to measure the pH, made it impossible to measure the pH of the sample zone. These experiments led to an interest in the mobility of proton and hydroxide ions within the capillary. While extensive measurements had been performed on bulk solutions of strong acids and bases under an electric field, no one as yet had measured the mobilities on a capillary. Using a pH indicator to measure the migration velocity of the ions, the mobilities of OH⁻ and H⁺ ions were determined, and found to be similar to empirical measurements made using bulk solutions. Finally, in a departure from pH measurement, method development for the assay of functionalized dendrimer compounds was performed. A qualitative assay was developed and evaluated for linearity, quantitation limit, and specificity. The assay was also applied to samples of the compound prepared in a plasma sample matrix.
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