COMBINED ION MOBILITY TIME-OF-FLIGHT MASS-SPECTROMETRY STUDY OF ELECTROSPRAY-GENERATED IONS

A commercially available ion mobility spectrometer was interfaced to a custom-built linear time-of-flight (TOF) mass spectrometer for the pu rpose of examining electrospray-generated plumes. Ionic species that w ere separated in the ion mobility spectrometer could be selectively de termined with the TOF mass spectrometer. Tetraalkylammonium salts, a p eptide, and proteins were examined. Their ion mobility spectra typical ly comprised a few peaks; some of these mobility-resolved species prod uced characteristic electrospray ions, while others of lower relative mobility did not. The TOF mass spectra of cytochrome c, injected from the ion mobility spectrometer at an indicated temperature of 90 degree s C or lower, showed signs that were characteristic of protein-solvent clustering.