Desorption electrospray ionization using an Orbitrap mass spectrometer: exact mass measurements on drugs and peptides

Abstract
Desorption electrospray ionization (DESI) is implemented on an Orbitrap mass spectrometer. The ion source is described and applications which utilize the high‐resolution capabilities of the Orbitrap are emphasized, including the characterization of peptides and active ingredients in pharmaceutical tablets. Measurements are made in less than 1 s at a resolution of 60 000. The implications of the data for the mechanisms of DESI are discussed. Copyright © 2006 John Wiley & Sons, Ltd.