Date Thesis Awarded

5-2020

Document Type

Honors Thesis

Degree Name

Bachelors of Science (BS)

Department

Chemistry

Advisor

John C. Poutsma

Committee Members

Rachel E. O'Brien

Robert D. Pike

Jonathan Frey

Abstract

This study has two seemingly unrelated parts that come together remarkably in displaying the comprehensive interplay between chemical structure and properties as well as the variety of analytical applications of mass spectrometry.

The first part of this study describes the determination of thermodynamic properties of several non-protein amino acids using the extended kinetic method. This is a continuation of work started in the Poutsma lab in Spring of 2017. The non-protein amino acids (NPA) studied here hold notable relevance in their unique ability to be mis-incorporated into peptide chains, as shown by the Hartman group at Virginia Commonwealth University.[1] By understanding the effects of methylation on the NPA’s inherent thermochemical properties, such as proton affinity and ∆acidH , we acquire insight into how these species may alter the behavior of the peptide chains in which they are incorporated. We found the experimental ∆acidH of α-methylserine, L-penicillamine, and 3-methylthreonine to be 1379 ± 23, 1380 ± 18, and 1378 ± 23 kJ/mol respectively. Within bounds of reasonable uncertainty, these values agree with computational predictions done at the B3LYP/6-311++G**//B3LYP/6-31+G* level of theory.

The second part of this study examines the gas-phase tetramer of carbamazepine (CBZ), an active pharmaceutical ingredient in anticonvulsants.[2] Highly polymorphic, CBZ is well-suited for studying the fundamentals of the self-assembly process in organic crystals, and more information on base-level assembly is required for effective predictive models of organic crystallization.[2] Because typically only one polymorph of a drug is approved by the Food and Drug Administration as a pharmaceutical active ingredient, polymorphism is an important phenomena in the pharmaceutical industry. In this study, we used High-Field Asymmetric Ion Mobility Spectrometry and traditional mass spectrometry to characterize the tetramer of CBZ and evaluate its relative stability. We confirmed that an intensity anomaly existed in both the protonated and sodiated forms in which the tetramer is larger than the trimer or the pentamer; the tetramer is a magic number cluster. This agrees with STM data taken of CBZ monolayers by our colleagues at Notre Dame.

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