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Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins
Thesis (MSc)--Stellenbosch University, 2022.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867614134082732032 |
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| access_status_str | Open Access |
| author | Nell, Eugene Hermanus Jacobus |
| author2 | De Villiers, Andre Joubert |
| author_browse | De Villiers, Andre Joubert Nell, Eugene Hermanus Jacobus |
| author_facet | De Villiers, Andre Joubert Nell, Eugene Hermanus Jacobus |
| author_sort | Nell, Eugene Hermanus Jacobus |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/125151 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:47:12.516Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/125151 Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins Nell, Eugene Hermanus Jacobus De Villiers, Andre Joubert Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Liquid chromatography Tannins Separation (Technology) UCTD Thesis (MSc)--Stellenbosch University, 2022. ENGLISH ABSTRACT: Despite advances in commercially available high performance liquid chromatography (HPLC) instruments and software, complete separation of complex mixtures remains a challenge hindering the identification and quantification of their components. This is relevant in many industries with products ranging from foods and beverages to pharmaceuticals and cosmetics. Two-dimensional liquid chromatography, specifically online comprehensive two-dimensional liquid chromatography (LC×LC), where discrete fractions of effluent from a first dimension (1D) column are continuously transferred to a second dimension (2D) column, offers very good resolving power for these types of applications. This is due to the separation power of the two dimensions being multiplicative under ideal circumstances. Online LC×LC also offers the benefit of being a fully automated separation technique. However, online LC×LC is limited by the inherent requirement for very fast second dimension separations. This requirement is dictated by the fact that the second dimension run time must be equal to the time it takes to collect a first-dimension fraction, known as the sampling time. The sampling time must in turn be sufficiently short to prevent mixing of compounds that have already been separated in the first dimension during the transfer step. The current study was aimed at exploring a novel LC×LC methodology which is not limited to very fast 2D separations, but still retains the other advantages that are associated with LC×LC separations, including the ability to provide a complete overview of the constituents of complex mixtures in a fully automated manner. By decoupling the 1D sampling time and 2D analysis time, the 2D run times do not necessarily all have to be the same. We thereby aimed to develop a flexible method, with lower resolving power in regions with less complexity and more resolving power in regions with more complexity. To do this, a commercial multiple heartcutting valve and stop-flow operation were used to facilitate variable 2D gradient times in the online LC×LC separation of complex phenolic samples. Hydrophilic interaction chromatography (HILIC) and reversed phase liquid chromatography (RP-LC) was used in the 1D and 2D respectively. Three samples containing complex mixtures of proanthocyanidins were analysed to demonstrate the viability of the developed method in combination with UV and high-resolution mass spectrometric detection. A critical evaluation of the performance of the variable gradient time stop-flow HILIC×RP-LC method is presented, which shows that a significant gain in performance can be obtained compared to online HILIC×RP-LC separations of the same samples. AFRIKAANSE OPSOMMING: Ten spyte van die vooruitgang in kommersieël beskikbare hoëverrigtingvloeistofchromatografie (HPLC) instrumente en sagteware, bly die volledige skeiding van komplekse mengsels 'n uitdaging wat die identifikasie en kwantifisering van hul komponente belemmer. Dit is relevant in verskeie nywerhede met produkte wat wissel van voedsel en drank tot farmaseutiese produkte en skoonheidsmiddels. Twee-dimensionele vloeistofchromatografie, spesifiek aanlyn omvattende twee-dimensionele vloeistofchromatografie (LC×LC), waar diskrete fraksies van uitvloeisel van 'n eerste dimensie ( 1D) kolom voortdurend na 'n tweede dimensie (2D) kolom oorgedra word, bied baie goeie skeidingsvermoë vir sulke toepassings. Dit is weens die skeidingskrag van die twee dimensies wat onder ideale omstandighede vermenigvuldigend is. Aanlyn LC×LC bied ook die voordeel dat dit 'n volledig outomatiese skeidingstegniek is. Aanlyn LC×LC word egter beperk deur die vereiste vir baie vinnige skeidings in die tweede dimensie. Hierdie vereiste word bepaal deur die feit dat die tweede dimensie se looptyd gelyk moet wees aan die tyd wat dit neem om 'n eerste-dimensie fraksie te versamel, bekend as die monsternemingstyd. Die monsternemingstyd moet op sy beurt voldoende kort wees om vermenging van komponente, wat reeds in die eerste dimensie geskei is, tydens die oordragstap te voorkom. Die huidige studie was daarop gemik om 'n nuwe LC×LC metodologie te ondersoek wat nie beperk is tot baie vinnige 2D skeidings nie, maar steeds die ander voordele behou wat met LC×LC skeidings geassosieer word, insluitend die vermoë om 'n volledige oorsig van die komponente van komplekse mengsels te gee, op 'n volledig outomatiese wyse. Deur die 1D monsternemingstyd en 2D ontledingstyd te ontkoppel, hoef die 2D looptye nie noodwendig almal dieselfde te wees nie. Ons het daardeur beoog om 'n buigsame metode te ontwikkel, met 'n laer skeidingsvermoë in streke met minder kompleksiteit en meer skeidingsvermoë in streke met hoër kompleksiteit. Om dit te doen, is 'n kommersiële meervoudige hartsnyklep en stopvloei-operasie gebruik om veranderlike 2D gradiënttye in die aanlyn LC×LC skeiding van komplekse fenoliese monsters te fasiliteer. Hidrofiliese interaksiechromatografie (HILIC) en omgekeerde-fase vloeistofchromatografie (RP-LC) is onderskeidelik in die 1D en 2D gebruik. Drie monsters, wat komplekse mengsels van proantosianidiene bevat, is ontleed om die lewensvatbaarheid van die ontwikkelde metode in kombinasie met UV en hoë-resolusie massaspektrometriese opsporing te demonstreer. 'n Kritiese evaluering van die werkverrigting van die veranderlike gradiënttyd stopvloei HILIC×RP-LC metode word aangebied, wat toon dat 'n beduidende wins in werkverrigting verkry kan word in vergelyking met aanlyn HILIC×RPLC skeidings van dieselfde monsters. Masters 2022-03-11T10:46:07Z 2022-04-29T12:56:12Z 2023-01-04T03:00:15Z 2022-03 Thesis http://hdl.handle.net/10019.1/125151 en_ZA Stellenbosch University xi, 108 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Liquid chromatography Tannins Separation (Technology) UCTD Nell, Eugene Hermanus Jacobus Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title | Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title_full | Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title_fullStr | Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title_full_unstemmed | Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title_short | Improving comprehensive two-dimensional liquid chromatographic analysis of condensed tannins |
| title_sort | improving comprehensive two dimensional liquid chromatographic analysis of condensed tannins |
| topic | Liquid chromatography Tannins Separation (Technology) UCTD |
| url | http://hdl.handle.net/10019.1/125151 |
| work_keys_str_mv | AT nelleugenehermanusjacobus improvingcomprehensivetwodimensionalliquidchromatographicanalysisofcondensedtannins |