Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

AbstractThis review offers an introduction to the principles and generic applications of Fourier transform ion cyclotron resonance/mass spectrometry (FTICR/MS), directed to readers with no prior experience with the technique. The fundamental Fourier transform ion cyclotron resonance (FTICR) phenomenon is explained from a simplified theoretical treatment of ion behavior in idealized magnetic and electric fields. The effects of trapping voltage, trap size and shape, and other nonidealities are then manifested mainly as perturbations that preserve the idealized ion behavior modified by appropriate numerical correction factors. Topics include: effect of ion mass, charge, magnetic field, and trapping voltage on ion cyclotron frequency; excitation and detection of ion cyclotron resonance (ICR) signals; mass calibration; mass resolving power and mass accuracy; upper mass limit(s); dynamic range; detection limit, strategies for mass and energy selection for multiple mass spectroscopy (MSn); ion axialization, cooling, and remeasurement; and means for guiding externally formed ions into the ion trap. The relationship of FTICR/MS to other types of Fourier transform (FT) spectroscopy and to the Paul (quadrupole) ion trap is described. The article concludes with selected applications, an appendix listing accurate fundamental constants needed for ultrahigh‐precision analysis, and an annotated list of selected reviews and primary source publications describing various FTICR/MS techniques and applications in fuller detail.