Abstract

Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry.

The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary amines present in peptide and protein ions. In addition, strong non-covalent interactions have also been observed with arginine-containing peptides ions. Studies of their dissociation behavior as well as the nature of their interaction (i.e., covalent versus non-covalent) have been investigated. Application of this Schiff base ion/ion chemistry has been demonstrated on matrix assisted laser desorption/ionization (MALDI)-derived peptide ions. Such Schiff base ion/ion chemistry, whether electrospray or MALDI-derived, can produce complementary or even an increase in structural information. Multiple covalent modifications within one ion/ion encounter have been demonstrated on peptide and protein cations via Schiff base cluster anions. This dissertation also highlights the gas-phase transformation of phosphatidylcholine cations into demethylated phosphatidylcholine anions, which provides an increase in structural information upon activation. As a whole, gas-phase covalent and non-covalent ion/ion chemistry represents a promising new area for identifying and characterizing biological analytes.

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Committee Chair

Scott A. McLuckey

Date of Award

Fall 2013

First Advisor

Scott A. McLuckey

Committee Member 1

Mary J. Wirth

Committee Member 2

Mingji Dai

Committee Member 3

David H. Thompson

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