Fourier transform ion cyclotron resonance detection: principles and experimental configurations

Fourier transform ion cyclotron resonance mass spectrometry is based on image current detection of coherently excited ion cyclotron motion. The detected signal magnitude and peak shape may be understood from idealized behavior: single ion, zero-pressure, spatially uniform magnetic field, three-dimensional axial quadrupolar electrostatic trapping potential, and spatially uniform resonant alternating electric field. In practice, deviation from any of the above conditions will shift, distort, split, and/or coalesce FT-ICR mass spectral peaks. Fortunately, such peak distortions may typically be avoided by appropriate experimental design and/or greatly minimized by internal frequency-to-m/z calibration. Various aspects of modern FT-ICR detection (hardware and software) are discussed. (Int J Mass Spectrom 215 (2002) 59–75) © 2002 Elsevier Science B.V. All rights reserved.