| Popis: |
The first of the three parts of this study involves the construction of a large scale time-of-flight mass spectrometer. A large aluminium-alloy vacuum chamber was designed and manufactured. Ion trajectory modelling was carried out for defining the optimum ion optical configuration of the matrix-assisted laser desorption/ionisation (MALDI) ion source that was designed and constructed. A floating ion detector assembly was designed and installed. MALDI mass spectrometry experiments were performed with biomolecules and polymer samples. The second part of this work involves the design and construction of a MALDI ion source in the collision cell area of a four-sector tandem mass spectrometer. The apparatus makes use of an array detector installed as the detector of the second double-focusing mass analyser of this instrument. High resolution and sensitivity mass spectra of high mass biomolecules and polymer samples were acquired. Resolution in excess of 3500 full-width at half maximum (FWHM) has been observed. The third part of this work describes the theoretical considerations, the design the construction and the performance of a prototype magnetic sector/time-of- flight tandem mass spectrometer with an ideal time-focusing ion mirror as the second mass analyser (Mag-TOF). The method followed in order to overcome the inherent incompatibilities of the two mass-analysis stages is discussed. The theoretical description of the ideal time-focusing reflectron is presented, together with analysis of the time-aberrations of the delivery ion optics and the TOF part of the instrument, and their influence to resolution and sensitivity. Initial experiments have been performed to prove the feasibility of the operational principle of this prototype instrument. High resolution (approximately 3000, FWHM) tandem mass spectra of peptides are presented. The instrument also achieved high levels of sensitivity. |
