A microdevice for the improved presentation of biological samples for MALDI-TOF mass spectrometry

Hodgson, L 2009, A microdevice for the improved presentation of biological samples for MALDI-TOF mass spectrometry, Doctor of Philosophy (PhD), Applied Sciences, RMIT University.

Document type: Thesis
Collection: Theses

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Title A microdevice for the improved presentation of biological samples for MALDI-TOF mass spectrometry
Author(s) Hodgson, L
Year 2009
Abstract This thesis describes the development of a novel off-line sample separation and presentation system compatible with an existing Bruker Biflex MALDI-TOF mass spectrometer. More specifically, it describes the manufacture, characterisation and testing of a modified MALDI target that incorporates a removable insert coated with a customisable conductive polymer surface. The concept of this target design is not limited to the dimensions of the Bruker Biflex II mass spectrometer and can therefore be applied to MALDI-TOF instruments in general.

As the diverse nature of biological samples often complicates the sample-surface interactions leading to variability in MALDI results, it is desirable to be able to tailor the hydrophobicity/hydrophilicity of the target insert surface to enable a broader range of samples to be analysed. Two surface modification systems were assembled and treating protocols were developed to enable controlled exposure of the polymer surface. One of these, corona discharge treatment, achieved the desired surface modifications and was subsequently used. A full characterisation of the surface morphology and chemical structure was accomplished.

A novel open channel microfluidic sample delivery system was designed, manufactured and protocols were developed to deliver a standard peptide mixture to the surface of the target insert. An electrospray deposition apparatus was assembled to deposit matrix to the analytes on the target surface. The target insert was positioned within the modified MALDI target and mass spectra were obtained as the laser rastered along the surface.

The mass spectra obtained demonstrated that spatial separation of a standard peptide mixture has occurred without compromising the quality of the mass spectra. The difference in spatial distribution observed for treated and untreated CF-PE inserts indicated that manipulating the hydrophobic/hydrophilic character of the CF-PE surface of target inserts has considerable potential as a sample separation and presentation device for MALDI-TOF mass spectrometry. Although the separation afforded by the device was restricted by the area available for separation on the target surface. These results are promising and may offer an alternative to the inclusion of traditional LC and CE separation techniques for protein mass spectral analysis.
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Applied Sciences
Keyword(s) Proteomics
MALDI-TOF Mass Spectrometry
Corona discharge
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Created: Mon, 29 Nov 2010, 10:50:16 EST
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