Purdue University Graduate School
Nicole Brundridge dissertation (FINAL).pdf (5.99 MB)


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posted on 2024-04-04, 13:02 authored by Nicole Michelle BrundridgeNicole Michelle Brundridge

Metal ions are typically considered a nuisance for mass spectrometry, as they can introduce chemical noise and distribute an analyte’s signal into multiple peaks. In some cases however, metal ions in biological solutions are either necessary for biomolecular structures, or so ubiquitous in a sample’s native solution conditions that they are difficult to fully remove. In this work, the role of metal ions in biological analytes is explored. For analytes that require metal ions to maintain higher order structures, a mass spectrometry method was developed to determine whether a stable structure is formed from metal ion adducts, or if the metal ion adducts are nonspecifically bound. Electron transfer of these structures reveals complementary fragmentation information, with the added discovery of new radical fragmentation pathways. With mass spectrometry, specific ligand and metal ion affinities can even be determined for analytes at low enough concentrations. In addition to analytes that require metals, an exploration on unwanted metal ion adduction during the electrospray ionization process is shown via gas-phase ion/ion reactions. Observing how specific anionic ligands exchange metals with protons from proteins on a small and controlled scale gives a greater understanding of what solutions can lead to the cleanest results. In addition, this work shows the possibility of finding anionic ligands that will instead exchange protons with metal ions found on proteins. In the gas-phase, these experiments have a high degree of control, leading to a much greater understanding of how metal ions influence mass spectrometry samples.


Degree Type

  • Doctor of Philosophy


  • Chemistry

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Scott A. McLuckey

Additional Committee Member 2

Danzhou Yang

Additional Committee Member 3

Julia Laskin

Additional Committee Member 4

Chengde Mao