Gas phase analysis of biomolecular ions in a quadrupole ion trap: Protein analysis and instrumentation

Abstract

Ion/ion reactions were performed in a quadrupole mass spectrometer in order to facilitate top down protein identification, charge reduction, and charge inversion. The first portion of the dissertation is focused on original instrumental development of an electrospray interface optimized to efficiently transmit ions generated from electrospray through the ring electrode. Additionally, emitter voltage manipulation schemes to enable more robust ion/ion reaction capacity from duel emitters on a single source were also developed. The second portion of the dissertation focuses on a series of proton transfer ion/ion reactions that are used for distinctly different applications. A top-down protein identification strategy for complex protein mixtures was derived from post ion/ion mass spectra formed from a series of ion-parking, collision-induced dissociation, and proton transfer reaction steps. Simple proton hydrate clusters were utilized to facilitate proton transfer reactions that successfully charge reduced intact Arixtra molecules by partitioning some portion of the ion/ion reaction exothermicity into the desolvation of the proton hydrates. Finally, a sequential ion/ion reaction scheme was used to generate radical [M-2H]-. protein anions that were charge inverted [M]+. cations via a proton transfer reaction