Peptide studies using a fast atom bombardment high field mass spectrometer and data system. 1—Sample introduction, data acquisition and mass calibration

Conditions were established for analyzing as little as 5 pmol of an underivatized peptide delivered in a glycerol sample matrix as a thin film onto a gold-plated copper sample stage and then bombarded with xenon fast atoms. Calibration of the fast atom bombardment high field mass spectrometer and data system was achieved using cesium iodide/glycerol as a reference. Calibration at several accelerating potentials permitted a mass range from 393 to 5941 u. Several factors were examined that contribute to the quality of the mass spectrum: components within the glycerol such as other peptides, alkali salts, acid and reducing agents; the nature of the fast atom gas; concentration of the peptide delivered to the sample stage; and the effect of the sample stage and sample matrix on sensitivity.