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Mapping of charged carbohydrates in chemical pulps employing conductometric titration and capillary zone electrophoresis: application and development
2003 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Pulp samples obtained after each step in four different bleaching sequences, and a liner pulp, have been studied with respect to total fiber charge and carbohydrate composition. The study of the fiber charge, which has been done by means of conductometric titration, has shown that the total fiber charge decreases throughout the bleaching sequences. The carbohydrate composition of the pulps has been determined using capillary zone electrophoresis with preceding enzymatic hydrolysis and derivatization of the carbohydrate monomers through reductive amination in order to make direct UV-detection possible. These analytical runs have shown that hexenuronic acid, in combination with a small portion of 4-O-methylglucuronic acid, to a large extent explains the total fiber charge in unbleached pulp. It has further been established that the bleaching sequences give rise to a reduction of the hexenuronic acid content. The total fiber charge, though, has been proved not to diminish to the same extent as the hexenuronic acid content and in chlorine dioxide bleached pulp only 23% of the fiber charge has been explained by hexenuronic acid and 4-O-methylglucuronic acid. Sugar acids substituted in C-1 position cannot be derivatized through reductive amination and a new capillary zone electrophoresis method, based on indirect UV-detection and modification of the capillary inner wall with a cationic surfactant, has been employed to detect such species. A number of sugar acid standard solutions have been run in the capillary zone electrophoresis instrument, according to this method, and the results were satisfactory. Reproducible results have not been obtained from runs of enzyme hydrolysate. Chlorine dioxide bleached pulp has been subject to acid hydrolysis and the hydrolysate has been analyzed with capillary zone electrophoresis according to the new method. A peak was obtained, which, through spiking of the sample with acid standards, has been identified as xylonic acid.

Place, publisher, year, edition, pages
2003.
Keywords [en]
Technology
Keywords [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-42946ISRN: LTU-EX--03/080--SELocal ID: 0e2b2ba9-7fce-4a15-84fd-5251d24343c6OAI: oai:DiVA.org:ltu-42946DiVA, id: diva2:1016173
Subject / course
Student thesis, at least 30 credits
Educational program
Chemical Engineering, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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CiteExportLink to record
Permanent link

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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf