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The dynamic modification of gas chromatographic stationary phases by vapours
Thesis (DPhil)--University of Pretoria, 1998.
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| Format: | Thesis |
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University of Pretoria
2021
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| _version_ | 1867613679823880192 |
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| access_status_str | Open Access |
| author2 | Rohwer, Egmont Richard |
| author_browse | Rohwer, Egmont Richard |
| author_facet | Rohwer, Egmont Richard |
| collection | Thesis |
| dc_rights_str_mv | © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (DPhil)--University of Pretoria, 1998. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/82522 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:39:59.298Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/82522 The dynamic modification of gas chromatographic stationary phases by vapours Rohwer, Egmont Richard Chen, Guay-Chuan UCTD gas chromatographic stationary phases by vapours Thesis (DPhil)--University of Pretoria, 1998. A general method for the modification of stationary phase selectivity by vapours in capillary gas chromatography is presented. The modification is temporary and reversible. There are two approaches. The first procedure involves injection of a modifier of low volatility, as a large vapour plug, onto a capillary column at an elevated temperature. At subsequent lower analysis temperatures, the elution of the modifier is so slow as to enable the normal use of the flame ionization detector(FID). A silicone phase was modified to achieve chiral separation and the polarity of a polyethylene glycol column was significantly increased by this dynamic procedure. The reversible nature of the process presents a convenient way to study intermolecular interactions and potential selectors for novel GC stationary phases. In the second approach, a volatile modifier is continuously added to the carrier gas. Water vapour, to which the Fl D shows no response, was used to alter the retention properties of a polyethylene glycol coated capillary GC column. A dramatic increase in hydrogen bonding interactions was observed towards alcohols and carboxylic acids. The Kovats index of methanol was found to increase by 353 units. The application of the dynamically modified stationary phase to the analysis of alcohol additives in petrol was investigated. Dynamic modification of stationary phases can be performed with minimum alteration to existing equipment. Special selectivity can be obtained without the need for expensive custom-made columns. Chemistry DPhil Unrestricted 2021-11-02T10:19:51Z 2021-11-02T10:19:51Z 2021 1998 Thesis * http://hdl.handle.net/2263/82522 © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD gas chromatographic stationary phases by vapours The dynamic modification of gas chromatographic stationary phases by vapours |
| title | The dynamic modification of gas chromatographic stationary phases by vapours |
| title_full | The dynamic modification of gas chromatographic stationary phases by vapours |
| title_fullStr | The dynamic modification of gas chromatographic stationary phases by vapours |
| title_full_unstemmed | The dynamic modification of gas chromatographic stationary phases by vapours |
| title_short | The dynamic modification of gas chromatographic stationary phases by vapours |
| title_sort | dynamic modification of gas chromatographic stationary phases by vapours |
| topic | UCTD gas chromatographic stationary phases by vapours |
| url | http://hdl.handle.net/2263/82522 |