Characterization of noncovalent complexes by electrospray ionization (ESI) Fourier transform mass spectroscopy (FTMS)

The first chapter provides a brief introduction of the significance and methodology of studying non-covalent complexes in gas phase by mass spectrometry. It also explains the theory and instrumentation of electrospray ionization (ESI) source and Fourier transform mass spectrometry (FTMS).; The second chapter covers the preliminary results of heated capillary dissociation (HCD) method. Cyclodextrin peptide complexes are examined by this method. A good agreement is found between the relative order of stability obtained by HCD and collision induced dissociation (CID). A mechanism is proposed to account for the observed relative order.; Chapter three introduces a new design of a differentially heated capillary. The new design of the capillary is implemented to answer whether the dissociation during HCD experiments is in gas phase or solution phase. Relative stability is determined for cyclodextrin amino acid complexes. Evaluation of activation barrier E_a and preexponential factor A are attempted.; Chapter four utilizes the HCD method and differentially heated capillary developed in this laboratory to characterize inclusion complexes versus non-inclusion complexes. Amino acids are complexed to cyclodextrin and its linear analog—maltoheptaose. Methods are developed to differentiate inclusion complexes and non-inclusion complexes.; Chapter five extends our knowledge and methodology on model non-covalent complexes to more complicated systems: protein substrate complexes. Results indicate that lysozyme complexes follow the same stability in gas phase as in solution phase. Specific complexes with substrates are found have different CID behavior than non-specific complexes. Possible gas-phase enzymatic activity has been explored.; Chapter six describes a novel intermolecular endothermic proton transfer reaction. While endothermic proton transfer is relative common in many important reactions, the direct evidence is elusive. This reaction also provides the possibility for site-selective fragmentation of oligosaccharides specified by the coordination.