The electrospray ion mobility mass spectrometer is used for a variety of projects including structural studies and investigations of biomolecule hydration. A schematic of the experimental setup is shown below. Ions are formed by electrospray ionization and transferred into the vacuum system via a capillary followed by an ion funnel, which is also used as an ion-storage and pulsing device. Ions are then injected into a drift cell and are pulled through by a weak electric field. In mobility experiments, the cell is filled with several Torr of helium. In temperature-dependent equilibrium experiments, the cell contains a neutral reactant gas. Ions exiting the cell are mass analyzed in a quadrupole mass spectrometer, and finally detected. A more detailed description of the instrumentation can be found on this site here and published in the literature [Wyttenbach, T.; Kemper, P. R.; Bowers, M. T. Int. J. Mass Spectrom. 2001, 212, 13].