Abstract
In biological systems, carbohydrates serve a critical role in cell signaling, immune response, and protein folding, as well as function as biomarkers for certain disease states based on the abundance and types of carbohydrates present. Carbohydrates are difficult to analyze due to limited sample size and the high degree of isomerism in these structures. Mass spectrometry (MS) is a technique that is sensitive to micromolar concentrations and can be used to detect carbohydrates regardless of isomeric features. This dissertation investigates MS analysis of carbohydrates through rapid labeling and the effect of the emitter used during electrospray ionization (ESI).
Chapter One discusses the biological importance of carbohydrates and how they
can be analyzed using analytical techniques – specifically MS. Chapter Two is a
comprehensive review of how carbohydrates can be studied using hydrogen/deuterium exchange (HDX) with MS. HDX is a technique that has been adapted for rapid labeling of carbohydrates to distinguish isomeric species as well as give insight into their solvated conformations. Chapter Three examines the effect of spray solvent pH on the rapid HDX of carbohydrates and peptides during the process of ESI. Due to ESI being an electrochemical process, the trend in deuterium uptake as pH shifts appears different from bulk-solution trends. Notably, distinct functional groups have different trends of exchange and exhibit different shifts in deuterium uptake as pH changes. Chapter Four examines methods for establishing rapid mixing using theta emitters and provides insight
into how to generate emitters of different sizes for creating distinct reaction times for solution-phase mixing during ESI. Finally, Chapter Five looks at the utility of an interior coating of polyethylene glycol (PEG) on ESI emitters for the analysis of carbohydrate-containing compounds. This PEG-coating on submicron emitters was found to block the leaching of sodium, thus affecting the formation of carbohydrate-metal adducts. Together, this work enables a more comprehensive analysis of carbohydrates by revealing how conditions before droplet formation during ESI influence generated spectra and rapid-mixing experiments.
Chapter One discusses the biological importance of carbohydrates and how they
can be analyzed using analytical techniques – specifically MS. Chapter Two is a
comprehensive review of how carbohydrates can be studied using hydrogen/deuterium exchange (HDX) with MS. HDX is a technique that has been adapted for rapid labeling of carbohydrates to distinguish isomeric species as well as give insight into their solvated conformations. Chapter Three examines the effect of spray solvent pH on the rapid HDX of carbohydrates and peptides during the process of ESI. Due to ESI being an electrochemical process, the trend in deuterium uptake as pH shifts appears different from bulk-solution trends. Notably, distinct functional groups have different trends of exchange and exhibit different shifts in deuterium uptake as pH changes. Chapter Four examines methods for establishing rapid mixing using theta emitters and provides insight
into how to generate emitters of different sizes for creating distinct reaction times for solution-phase mixing during ESI. Finally, Chapter Five looks at the utility of an interior coating of polyethylene glycol (PEG) on ESI emitters for the analysis of carbohydrate-containing compounds. This PEG-coating on submicron emitters was found to block the leaching of sodium, thus affecting the formation of carbohydrate-metal adducts. Together, this work enables a more comprehensive analysis of carbohydrates by revealing how conditions before droplet formation during ESI influence generated spectra and rapid-mixing experiments.
| Original language | American English |
|---|---|
| Qualification | Ph.D. |
| Awarding Institution |
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| Date of Award | Jul 1 2024 |
| State | Published - 2024 |