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Title: Investigations of mass transfer in size exclusion chromatography by nuclear magnetic resonance
Author: Holland, Daniel Joseph
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2006
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The aim of this dissertation was to investigate and quantify the mass transfer processes occurring within a chromatography column by utilising Nuclear Magnetic Resonance (NMR). The dissertation describes the development of Magnetic Resonance Imaging techniques to enable the quantitative imaging of urea and lysozyme in one-, two- and three-dimensions, in situ and without chemical labelling. These images reveal the evolution of the distribution of both species simultaneously, and hence highlight that much of the distortion to the concentration distribution in the column arises from the inlet distributor. In addition to these novel imaging protocols, alternating pulsed gradient stimulated echo (APGSTE) NMR was used to obtain quantitative information on the microscopic motion of molecules over time periods from a few milliseconds up to two seconds. This enables quantitative measurement of eddy dispersion, mass transfer between mobile and stagnant liquid, and longitudinal diffusion. These effects can then be used to predict the microscopic (i.e. over displacements < 20 particle diameters) dispersion to within 25% over a range of flow rates. Furthermore, spatially resolved pulsed gradient stimulated echo NMR was used, in conjunction with the MRI techniques developed previously in this work, to isolate and quantify the effect of the inlet distributor and the packing heterogeneity on the macroscopic dispersion. Finally, a preliminary investigation of the influence of macroscopic flow heterogeneity on SEC protein refolding was performed. This confirmed an earlier hypothesis that sample distribution at the inlet of the column dominates the final refolding yield in SEC refolding reactors.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available