A scaling technique for studying the dynamics of high mass ions in fourier transform mass spectrometry: a preliminary report

The signals that have been observed for high mass biomolecule ions in Fourier transform mass spectrometry (FTMS) are characterized by low signal-to-noise and low resolution at low ion number whereas the spectral peaks for more moderate mass ions are good with high signal and resolution. We have proposed that the behavior of target high mass ions can be experimentally investigated with low mass ions at lower magnetic inductions. The justification of this proposal derives from the observation that solutions to the equations of motion for high and low mass ions are the same if the time parameter of the solution is scaled, and if the appropriate adjustments to the magnet induction are made. New results obtained for the molecular ion of benzene at lower magnet inductions support the relevance of scaled experiments for studying problems that occur at high mass. High mass ions modeled with the benzene molecular ion show good signal and resolution that degrades as the target mass is increased. Increasing the ion number improves the signal and resolution. Compensating the cubic trap improves signal and resolution for moderate ion numbers. This suggests a partial remedy for the problems at high mass.