Capillary electrochromatography and capillary electrophoresis for the analysis of biological and environmental analytes

Capillary electrochromatography (CEC) offers the combined attributes of micro-high performance liquid chromatography (HPLC) and capillary zone electrophoresis (CZE). In the thesis technical aspects in CEC were explored including column-packing techniques, frit fabrication, column performance stability, and durability. A simplified slurry-packing procedure was refined for making 50 μm I.D. CEC columns that produced comparable performance to commercial columns. Evaluation of a single column over an extended period gave precision of 0.6–5.6% RSD for k′ value, and 3.7–10% RSD for N value, with N from 60,000–213,000 plates/m. The variation from column to column (n = 5) gave precision within 0.94% RSD in migration time, 17% RSD in theoretical plates and 6.9% RSD in resolution. The influences of sample loading, solvent ionic strength, organic solvent concentration, buffer pH, electric field and gap formation on separation efficiency and migration time were investigated.; CEC methods for analysis of 19 phenylthiohydantoin amino acids (PTH-AAs), 4 testosterone metabolites and 16 polycyclic aromatic hydrocarbons (PAHs) have been developed using thermo-optical UV absorbance detection (TOAD). A quantitative analysis of in vitro testosterone metabolites, transformed by Cytochrome P450 isozymes, was included to show the applicability of CEC in pharmacokinetics studies. CEC was demonstrated as a viable alternative technique to both HPLC and CZE in analysis of a certain range of hydrophobic compounds.; Non-aqueous CE coupled with electrospray ionization and mass spectrometric detection (CE/ESI/MS) was developed for drug screening of Fritillaria alkaloids. The method allowed baseline resolution of 10 stereoisomeric alkaloids and simultaneous quantitation in much shorter analysis times than GC/MS or LC/MS methods.; Micellar electrokinetic chromatography (MEKC) using bile salts and organic modifiers was shown as applicable, efficient and cost-effective in separation of PAHs. Multiconformational bile salt aggregates and organic modifiers were found to play a significant role in determination of the electrophoretic mobilities of PAH.; Two mathematical approaches were proposed to correct the migration time variations of multiple analytes in MEKC. By using the migration markers, the precision of migration was dramatically improved to less than 0.6% for PTH-AAs, 0.4% for FTH-AAs, and 0.03% for oligosaccharides compared to 1%, 4%, and 3% respectively, without correction.