Improvements to the analytical capabilities of Fourier transform ion cyclotron resonance mass spectrometry

Improvements to the utility of Fourier transform ion cyclotron resonance mass spectrometry for analytical mass spectrometry are presented. Various ion packet decay models are investigated for both singly and multiply charged ions. A new ion trap allows for determination of the cyclotron radius of the ion packet with improved sensitivity. The cyclotron radius of the ion packet can be measured to levels as low as 30% of the maximum allowed radius by measuring the ratio of the third harmonic to the fundamental single. An experimental protocol is developed to determine the number of ions in the detected ion packet. The detection limit and dynamic range of the mass spectrometer are now defined relative to the number of ions in the orbiting coherent ion packet. The detection limit of an Extrel FTMS 2000 is 177 ions at a signal-to-noise ratio of 3:1. These advances allow for the experimental investigation of post-excitation ion packet decay models presented for FT/ICR/MS. A fast neutral beam ionization source has been optimized for SIMS type experiments on conductive and insulating materials. The use of an open-ended ion trap with a pulsed ionization source are shown to greatly improve the detected signal. Advantages of this ionization source for the analysis of insulating polymers is discussed. An electrostatic ion guide has been designed and constructed which simplifies the use of high pressure ionization sources and the FT/ICR mass spectrometer. The electrostatic ion guide allows for the efficient injection of low energy externally formed ions without additional focussing or acceleration to the ion packet. The properties and advantages of this ion injection device are demonstrated for a thermionic emitter ionization source. An rf glow discharge ionization source and the electrostatic ion guide allows for the improved elemental analysis of solid samples.