Development of electrospray ionization of biomolecules on a magnetic sector mass spectrometer

The initial part of this study involves developments made on an electrospray ionization (ESI) source installed on a large-scale double-focusing reverse-geometry two-sector mass spectrometer. The practical considerations and some basic theory have been given in this thesis for each of the improvements made to the ESI source. The process of partial re-designing the ion optical system showed that the ion beam was affected by both gas dynamics and by the field penetration from the lenses of the ion optical system in the region immediately after second skimmer. More than one order magnitude stronger ion signal intensities at the mass spectrometer final detector and easier ESI source operation conditions and stable ion signals has been achieved. Mass-analyzed ion kinetic energy spectroscopy (MIKES) of different charge-states of relatively small peptides (substance P and bradykinin) for collision-induced dissociation (CID) and the metastable dissociation was carried out successfully. The translational energy losses caused shifts in the fragment ion peaks in the CID spectra, compared with fragment ion peaks in the metastable dissociation spectra. A major part of the study concerned effects of ESI source condition on the charge state distributions of mass spectra. It has been shown that the ion optical effect of the potential difference (V sub H sub C sub T sub - sub S) between the heated stainless steel capillary (HCT) and the first skimmer in the intermediate-pressure region (capillary-skimmer region or orifice-skimmer region) of the ESI source was the main factor in determining the charge state distribution of the ESI mass spectra. The temperature of the HCT and the potential difference between the first skimmer and the second skimmer has been shown to be also important factors. The collision-induced dissociation (or so-called capillary-skimmer dissociation) effect of V sub H sub C sub T sub - sub S has been shown to be relatively low in this sector-mass spectromete