Detection of high-mass biomolecules in Fourier transform ion cyclotron resonance mass spectrometry: theoretical and experimental investigations.

A simple modification to an ion cyclotron resonance (ICR) cell for detection of high-mass ions with large spatial and kinetic energy distributions is described. The modification consists of a copper wire positioned inside the ICR cell running parallel to the magnetic field lines. The wire acts as an ion guide to position the ions at the exact center of the ion cell. Ion trajectories are calculated using SIMION, and the predictions based on the calculations are compared with the experimental results. The results presented in this paper show that the ion-guide ICR cell can be used to detect singly charged biomolecule ions of up to 157,000 Da.