| There are two areas of focus in this work. First, oxidative detection at copper electrodes is extended to new analytes. Second, new electrochemical cell configurations for use in capillary electrophoresis with electrochemical detection (CEEC) are explored.;Constant potential amperometric detection of oligosaccharides, cyclodextrins, and polysaccharides following flow injection analysis (FIA), HPLC, and capillary electrophoresis (CE) has been accomplished at metallic copper electrodes. Additionally, cardiac glycosides following FIA and HPLC and aminoglycoside antibiotics following CE have been detected at the copper electrode.;Because alignment of capillary and electrode is a critical factor in the success of CEEC analyses, new electrochemical cell designs which improve the ability of the user to align the capillary are explored. Wall-jet copper electrodes provide some improvement in the ease, reproducibility, and stability of alignment, however, by integrating the capillary and electrode into one unit, no alignment procedures are required during CE setup.;The integration of capillary and electrode is accomplished by sputter coating a thin, conductive metal film directly onto the capillary tip, forming on-capillary electrodes (OCE). The OCE configuration provides much faster and simpler CE setup and highly stable and reproducible oxidation currents. Analysis of catechol compounds at Au-OCE, carbohydrates at Cu-modified Au-OCE, glucose at glucose oxidase modified Pt-OCE, and aminoglycoside antibiotics at Cu-OCE demonstrate the versatility of the OCE concept.;Finally, dual capillary-capillary electrophoresis (DCCE) with paired-OCE is used to provide dual-parallel electrochemical detection following CEEC. The equivalent separation characteristics of single capillary-capillary electrophoresis (SCCE) and DCCE is demonstrated by the analysis of catechol compounds at single and paired Au-OCE. The DCCE system is utilized as a dual-parallel electrode system with paired Au-OCE for the identification of catechol compounds at varied voltage and the selective detection of phenolic compounds at paired Pt-OCE. The system is further developed by employing paired-OCE of different electrode materials. |
