Approaching the Complexity of Biological Specimen: New Mass Spectrometry Concepts in Ambient Ionization and Proteomics

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.

Department dc:contributor.department

Chemistry

Year dc:date.issued

2024

Author dc:creator

• McPhail, Julia

Advisor dc:contributor.supervisor

• Oleschuk, Richard

• mass spectrometry
• proteomics
• ambient ionization
• analytical chemistry
• food chemistry

Statement dc:rights

• Attribution-NonCommercial-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-nd/4.0/

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/34138

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/34138