New development of theory and application in capillary electrophoresis: Extended dissociation model for predicting electroosmotic mobility, correction of electrokinetic sampling bias, and enantiomeric separations

Although the theoretical research of capillary electrophoresis (CE) is quite active in past twenty years and the technology of capillary electrophoresis has been accepted and widely used in chemical and pharmaceutical industries, quantitative control of electroosmotic mobility, the driving separation force in capillary electrophoresis, is still very limited. So far, there was no thorough study conducted on the quantitative control of electroosmotic mobility from theoretical approach. In this thesis, a new equilibrium ion adsorption model was developed based upon the chemical kinetic theory and Langmuir isotherm theory. This theory was successfully confirmed by the experimental results.; In Chapter 1, a historical review of the development of capillary electrophoresis technology, the development of theories involved in CE, and the landmarks of the application of CE are presented.; In Chapter 2, the detailed derivation of the equilibrium ion adsorption model is provided. In addition, the theoretical model was verified by using three types of buffer systems: buffers containing monovalent cations only; buffers containing multiple cations; and buffers containing cations and neutral additives.; Chapter 3 presents the study of suppressing the electroosmotic mobility by using multiply charged cations along with the microemulsion system for the purpose of dual opposite injection, which further qualitatively confirmed the theoretical model described in Chapter 2. An improvement of bias correction factor for an electrokinetic injection of sample was also presented.; Chapter 4 presents a development of a new analytical method for the quantitation of chiral impurities in sertraline hydrochloride, a therapeutic drug. The highly sulfated γ-cyclodextrin was used as the chiral selector. The method is capable to separate and accurately quantitate the stereoisomeric impurities at 0.1% of the active. In addition, the van't Hoff plot demonstrates a non-linear relationship between ln α and 1/T. The effect of temperature on separation also supported by the theoretical model described in Chapter 2.