Expanding and enhancing the capabilities of the quadrupole ion trap mass spectrometer for high -resolution and MSn analyses

The quadrupole ion trap mass spectrometer has been shown to be a versatile tool for the analytical chemist since its commercialization over 15 years ago. Despite its demonstrated abilities, areas for improvement still remain. This work has focused on two such areas: routinely obtaining the high resolutions necessary to implement exact mass measurement on the ion trap: and developing a method of producing reproducible and informative product ion spectra from collisionally induced dissociation.;After careful study of how ions can be ejected from an ion trap with high resolution using conventional ejection techniques, a novel way of ejecting ions with enhanced resolution was developed and refined. In contrast to the conventional ion ejection techniques, this new technique was shown to be very tolerant of the pressure of the buffer gas present in the ion trap. It was also shown to be capable of resolving isotopic envelopes that were incapable of being resolved using conventional methods. With this development, the ion trap is now capable of attaining the resolutions necessary for exact mass measurement.;Additionally, the process of generating fragment ions from a selected precursor ion was studied and ultimately improved. Formerly, a single excitation voltage was applied to the ion of interest in order to generate energetic collisions with the buffer gas present in the ion trap. This was all inefficient means of generating informative fragment ions since selecting the correct excitation voltage depends on many parameters. An improved approach was developed where several excitation voltages are applied to the ion of interest such that the possibility of generating fragment ions is greatly enhanced without a priori knowledge of an appropriate excitation voltage.;Together, these two advancements help to expand and enhance the capabilities of the quadrupole ion trap mass spectrometer so that it may continue to be a powerful tool for analytical chemists in the future.