Electrokinetic capillary chromatography methods for separation and trace enrichment of dilute analytes using open tubular and packed capillaries.

摘要

Scope and method of study. This research focused on furthering the development of electrically-driven microcolumn separation techniques, namely capillary electrophoresis (CE) and capillary electrochromatography (CEC), by contributing novel separation media and detection approaches at trace levels. The CE studies introduced micellar electrokinetic capillary chromatography methods for the separation and on-line preconcentration of small molecules. The CEC investigations were concerned with the introduction of on-line trace enrichment from dilute samples prior to separation, which are pertinent to environmental analysis. In addition, a novel separation system was introduced, and consisted of surfactant-rich mobile phases for use in CEC and the technique is called surfactant mediated capillary electrochromatography.; Findings and conclusion. Capillary electrophoresis and capillary electrochromatography proved to be powerful analytical tools for the separation and When combined with on-column preconcentration, minute amounts of both total and individual amounts of pesticides were readily detected in fortified deionized, tap, and lake waters. In on-line preconcentration schemes using segmented capillaries, the pesticides investigated were baseline separated with limits of detection of 10-8--10-9 M. With surfactant mediated capillary electrochromatography, several of the pyrethroids diastereomers and geometric isomers were readily separated in the presence of a charged surfactant (e.g., sodium di-2-ethylhexyl sulfosuccinate) in the running hydro-organic mobile phase.