Approaching the Complexity of Biological Specimen: New Mass Spectrometry Concepts in Ambient Ionization and Proteomics
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Authors
McPhail, Julia
Date
2024-10-28
Type
thesis
Language
eng
Keyword
mass spectrometry , proteomics , ambient ionization , analytical chemistry , food chemistry
Alternative Title
Abstract
Mass spectrometry (MS) is a powerful analytical technique that allows for the identification and quantification of molecules within a sample and therefore a valuable technique when analyzing complex biological specimen. Herein, two MS techniques in ambient ionization and proteomics are utilized to explore new concepts in food samples. First, a proof-of-concept is carried out with the liquid micro-junction surface sampling probe (LMJ-SSP), a liquid extraction-based ambient ionization probe, by replacing the tip with a 21-gauge needle. This creates the sharpened-LMJ-SSP, allowing for subsurface and depth profiling of limes. Lime layer characterization is performed using data-dependent acquisition, identifying important compounds such as malic acid, citric acid, and quinic acid. Depth profiling is performed by constructing an automated syringe pump system, where the sharpened-LMJ-SSP can be inserted into a lime at a constant speed, while monitoring the change in product ion at m/z 133.0 and m/z 191.0. The change in product ion is successfully monitored and this investigation shows promise for the sharpened probe. Second, different sample preparation methods are performed for high-throughput high-resolution mass spectrometry protein characterization of human milk. Human milk samples are fractioned into skim milk, milk fat globule membrane, whey, and casein using low and ultra centrifugation methods. In-gel digest, in-solution digest, and filter aided sample preparation (FASP) methods are performed. Additional variations in sample preparation were explored such as performing an acetone precipitation prior to digestion, different size filter membranes, and utilizing sodium dodecyl sulfate in FASP to determine the optimal sample preparation method.
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Attribution-NonCommercial-NoDerivatives 4.0 International
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivatives 4.0 International