Title page for ETD etd-03132003-161136


Document Type Doctoral Thesis
Author Venter, Andre
Email ventandre@gmail.com
URN etd-03132003-161136
Document Title Comprehensive two-dimensional supercritical fluid and gas chromatography (SFCxGC)
Degree PhD
Department Chemistry
Supervisor
Advisor Name Title
Prof E R Rohwer
Keywords
  • SFCxGC
  • modulation
  • petrol analysis
  • diesel analysis
  • supercritical fluid chromatography
  • fast temperature programmed gas chromatography
  • multidimensional chromatography
  • comprehensive chromatography
  • SFC
  • oxygenate analysis
  • essential oil analysis
  • modulator
  • fuel analysis
Date 2003-02-15
Availability unrestricted
Abstract
A novel chromatographic method was devised that makes use of the superb group separation power of normal phase supercritical fluid chromatography (SFC) combined with a fast second separation by a resistively heated gas chromatograph (GC). The SFC was operated isothermally with stopped flow to provide the time required for the GC analysis. The GC analysis had a typical cycle time of 1 minute. During this time the GC column was independently heated at a rate of 450C/min to 250C and actively cooled down again to -50C before the next GC injection takes place. This was achieved with an in-house designed, resistively heated, temperature programmable gas chromatograph. Various temperature measurement circuits were also evaluated. An interface was developed that allows transfer between the SFC and the GC in such a way that the entire eluent from the first separation is analysed by the second separator. Chromatographic resolution was not lost during the transfer process from the first to the second separation stages. The interface also allows for the exchange of the carrier gas used in the second gas chromatographic separation to provide for the maximum separation speed. In the first separation, a silica gel packed column and the novel application of a silica gel porous layer open tubular capillary column was used for SFC group separation. The SFCxGCftp was applied to petrochemical samples and essential oils and the results were compared to that obtained with a commercially available GCxGC system.
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  00front.pdf 174.80 Kb 00:00:48 00:00:24 00:00:21 00:00:10 < 00:00:01
  01chapter1.pdf 127.20 Kb 00:00:35 00:00:18 00:00:15 00:00:07 < 00:00:01
  02chapter2.pdf 343.16 Kb 00:01:35 00:00:49 00:00:42 00:00:21 00:00:01
  03chapter3.pdf 234.19 Kb 00:01:05 00:00:33 00:00:29 00:00:14 00:00:01
  04chapter4.pdf 1.03 Mb 00:04:45 00:02:26 00:02:08 00:01:04 00:00:05
  05chapter5.pdf 207.04 Kb 00:00:57 00:00:29 00:00:25 00:00:12 00:00:01
  06chapter6.pdf 223.88 Kb 00:01:02 00:00:31 00:00:27 00:00:13 00:00:01
  07chapter7.pdf 159.57 Kb 00:00:44 00:00:22 00:00:19 00:00:09 < 00:00:01
  08chapter8.pdf 229.75 Kb 00:01:03 00:00:32 00:00:28 00:00:14 00:00:01
  09chapter9.pdf 949.33 Kb 00:04:23 00:02:15 00:01:58 00:00:59 00:00:05
  10chapter10.pdf 139.38 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
  11curriculumvitae.pdf 143.24 Kb 00:00:39 00:00:20 00:00:17 00:00:08 < 00:00:01

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