A rapid scanning square wave voltammetric detector has been developed for use with high performance liquid chromatography.The electrochemical cell used in the detector was designed so that the HPLC effluent flows through the center of a large diameter platinum disk electrode and is then forced to flow radially across the electrode surface. The arrangement of the electrodes in the cell was intended to result in large analytical currents while minimizing electrical resistance and analyte band spreading in the detection zone. The detector was evaluated in terms of its minimum detectable quantity, linear dynamic range, electrochemical efficiency, and analyte band spreading. The MDQ was found to be in the low parts per billion range for hydroquinone. The detector was shown to provide data that is qualitatively superior to data obtained by amperometric detection and was shown to be compatible with gradient elution HPLC over a broad range of solvent compositions.
A sensor based on the quartz crystal microbalance was also developed for use in flowing solvent streams. Quartz crystals were treated with various compounds to produce close - packed monolayer coatings which could interact with solutes entering the flow cell. The solute capacity was determined for one of the monolayer coatings and various factors that influence the magnitude of the OCM signal were investigated. These factors include the solvent flow rate, the solvent strength, solute molecular structure, and bonded phase molecular structure. The QCM sensor was found to be a convenient probe for conducting surface adsorption studies and the molar free energy of adsorption was determined for some chemically related solutes on an amine modified crystal. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/38427 |
| Date | 06 June 2008 |
| Creators | Roush, John Albert |
| Contributors | Chemistry, Anderson, Mark R., Glanville, James O., Long, Gary L., Mason, R.W., McNair, Harold M., Merola, Joseph S. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation, Text |
| Format | x, 138 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 27827042, LD5655.V856_1992.R687.pdf |
Page generated in 0.0019 seconds