This thesis explores the structures and structural changes of supramolecular host-guest systems, proteins, and other small molecules in the gas phase, utilizing a combination of computational modeling and experimental data. The primary instruments employed were a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) and an ion mobility mass spectrometer (IM-MS). In the IM-MS experiments, the focus was on investigating the binding behavior of cyclodextrin macrocycles—specifically α, β, and γ-cyclodextrin—with per-fluoroalkane substances (PFAS), which are pervasive environmental contaminants. This investigation involved measuring ion-neutral collision cross sections and using computational modeling to determine whether PFAS compounds bind inside or outside the cyclodextrin cavity. The results indicate that only β-cyclodextrin binds PFAS compounds internally, attributed to its seven-fold symmetry and the localized hydrogen bonding network across the macrocycle's secondary face. Conversely, α and γ-cyclodextrin appear to favor collapsing inward, enhancing internal hydrogen bonding while keeping the PFAS bound externally. The FTICR-MS instrument was used for time-resolved CRAFTI (TR-CRAFTI) collision cross section measurements on various systems, including tetraalkylammoniums (TAA), cytochrome C, and β-cyclodextrin host-guest complexes. This involved activating gas-phase ions using sustained off-resonance irradiation (SORI) activation, followed by a variable delay for collisional cooling. Subsequently, a CRAFTI measurement was conducted to obtain a timeresolved view of the collision cross section. Initial findings suggest the feasibility of measuring and modeling structural changes post-activation over varying time scales, ranging from approximately 100 milliseconds to 10 seconds, depending on the size and complexity of the system being studied.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-11417 |
| Date | 06 June 2024 |
| Creators | Mismash, Noah |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | https://lib.byu.edu/about/copyright/ |
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