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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fourier transform infrared spectrometric detection of chromatographic effluents: instrumental and methodological improvements using a flow cell interface

Johnson, Charles Clifford January 1985 (has links)
The Fourier Transform Infrared spectrometer (FTIR) has been used increasingly as a detector for various forms of chromatography. Clearly the most established marriage has been that of the Gas Chromatograph (GC) with the FTIR. GC-FTIR has been developed well beyond other forms. The main objective of this thesis, however, is to extend the FTIR as a detector to previously untested forms of chromatography using a flow cell interface. These forms of chromatography include High Performance Liquid Chromatography (HPLC), both normal-phase and reversed-phase, and packed-column Supercritical Fluid Chromatography (SFC). Normal phase HPLC-FTIR was demonstrated on not only analytical scale columns, but semi-preparative and microbore scales as well. Significant advantages, particularly with respect to the low solvent consumption, were found in the microbore HPLC-FTIR experiment. This led to the development of a chromatographically improved flow cell, the Zero Dead Volume (ZDV) HPLC-FTIR interface. The ZDV cell shows superior chromatographic characteristics and has unique spectrometric characteristics because of its unusual cross-section. Detection limits as low as 40 ng were observed. Extension to reversed-phase HPLC-FTIR required incorporation of the Flow Injection Analysis (FIA) technique of low-dispersion flowing extraction. The compounds separated by HPLC are extracted into an infrared-transparent solvent, and the extracted compounds are detected by similar means to normal-phase HPLC-FTIR. Investigation of SFC-FTIR incorporated a high-pressure, gold-lined lightpipe flow cell to detect the components separated by the supercritical C0₂/packed-column chromatograph. Several unusual spectrometric characteristics were noted. Detection limits as low as 50 ng were observed with SFC-FTIR. / Ph. D.

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