Use of conducting polymers for chromatography

Although conducting polymers have been studied for more than ten years, their use in liquid chromatography is still new. This thesis studies the chemical and electrochemical properties of conducting polymers for use in liquid chromatography. The use of these polymers both as novel stationary phases and as electrochemical detection systems was explored. Polypyrrole was chosen as an example throughout this study. The polymer was either electrochemically or chemically synthesized on various substrates. The properties of polypyrrole were characterized using chronoamperometry, chronopotentiometry, elemental analysis, cyclic voltammetry, electrogravimetry, scanning electron microscopy (SEM), energy-dispersive x-ray (EDX) analysis, and fast atomic bombardment mass spectrometry and the results indicated that the polymer was suitable for chromatographic studies. Specifically, it was found that polypyrrole had unique properties in anion exchange. It was also found that the polymer was thermally-sensitive. Hardware and systems for synthesis and characterization of the stationary phases were developed in the course of this work. Polypyrrole incorporated with chloride and dodecyl-sulfate was deposited on reticulated vitreous carbon (RVC) particles and silica based particles for use as liquid chromatographic stationary phases. The properties of the polypyrrole stationary phases were determined by elemental analysis, surface area analysis, SEM and EDX analysis. Studies using polypyrrole stationary phases in chromatography and electrochemically controlled liquid chromatography were characterized using a selection of test compounds. Both reversed-phase and anion exchange chromatographic behavior was found on the polypyrrole stationary phases, and separations using these mechanisms were achieved. Electrochemical control was found to be effective on RVC based polypyrrole stationary phases. A polypyrrole dispersed-mercury modified electrode was also developed in the course of this work. Its chemical and physical stability, as well as electrochemical sensitivity and selectivity were investigated. It was demonstrated that the electrode could be used in amperometric detection following HPLC separation. This study has indicated that it is possible for conducting polymers to be used in chromatographic separation and detection systems.