Masters Degrees (Chemistry and Polymer Science)

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Browsing Masters Degrees (Chemistry and Polymer Science) by browse.metadata.advisor "Adendorff, H. J. A."

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    Ligand modification of Pluronic F108 for use in immobilized metal affinity separation of bio-macromolecules
    (Stellenbosch : Stellenbosch University, 2002-03) Van Kralingen, Leon; Adendorff, H. J. A.; Bredenkamp, M. W.; Stellenbosch University. Faculty of Science. Dept. of Chemistry & Polymer Science.
    ENGLISH ABSTRACT: Inthis work we aim to put into place a system to separate or immobilise biomacromolecules by means ofimmobilised transition metal ions like nickel(II) or copper(II). Although the concept of immobilised metal affmity chromatography (IMAC) has been around since the early 1960's, the metal ions were always immobilised by covalent modification of the support matrix. Recently the concept of IMAC was applied to membranes, and again the metal ion was immobilised by covalent modification of the membrane surface. Inthis study we covalently modified the support matrix by attaching a linear, EDTA type ligand to the hydroxy end groups of a tri-block copolymer (polyethylene oxide (PEO)m = 129 - polypropylene oxide (PPO)n = 56 - polyethylene oxide (PEO)m= 129), Pluronic® F108. The middle block of this polymer, which is hydrophobic, will non-covalently adsorb onto the membrane surface through hydrophobic interaction. The hydrophilic outer blocks, with the ligand modified end groups, will associate with the aqueous substrate exposing the chelated metal ion for interaction with the bio-macromolecules. This affords a system which is recyclable, without replacing the membranes, simply by stripping the expired ligand modified-polymer and adsorbing fresh polymer. A series of model ligands and their complexes were synthesised and characterised, to study the coordination of the ligand around the metal ions. The model compounds were also essential in characterising the final product - the ligand modified Pluronic. Finally the ligand modified Pluronic was tested for its metal binding capabilities. This was done in aqueous solution by qualitatively comparing the UV-VIS spectra of the modified Pluronic with that of the model ligands and complexes. The spectra indicate that metal coordination does take place.