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Microfabricated pillar array columns for liquid chromatography

Friday, 11 December, 2009 - 17:00
Campus: Brussels Humanities, Sciences & Engineering campus
Hamed Eghbali
phd defence

Nowadays, there is an increasing demand for better analytical tools in
the -omics fields (genomics, proteomics, metabolomics,…), where ever
increasing numbers of minimal sample volumes need to be analyzed and
quantified in shorter time lapses. Since the performance of a
chromatographic bed is extremely sensitive to the bed homogeneity, the
present work uses microfabrication techniques from the microelectronics
industry to produce ordered pillar array beds that are perfectly
homogeneous. This approach allows to combine the advantages of a
perfectly ordered packing structure with the numerous advantages of
miniaturization, including reduced reagent consumption. In the present
thesis, it is demonstrated that the currently existing microfabrication
techniques are refined enough to achieve the theoretical performance
limit. Applying a hydrophobic monolayer to the outer surface of the
pillars, fast reversed-phase separations of a synthetic mixture could be
conducted at different mobile phase velocities. As a result, it is concluded
that these microfabricated columns could yield much faster separations
compared to the conventional packed bed. Subsequently, real-world
biological mixtures originating from two different bacterial strains are
separated while revealing 15 components in less than 1 minute,
illustrating that these columns can be useful for practical applications.
The presented microfabrication strategy could also be used to conduct
fundamental band broadening studies by designing and testing two
different channels displaying a different degree of heterogeneity. In
addition, it is also illustrated that the flat format of these pillar array
channels is ideally suited to make detailed in-situ video recordings of the
eddy-dispersion phenomenon.