Surface-induced dissociation on a MALDI-ion mobility-orthogonal time-of-flight mass spectrometer: Sequencing peptides from an in-solution protein digest

Peptide sequencing by surface-induced dissociation (SID) on a MALDI-ion mobility-orthogonal TOF mass spectrometer is demonstrated. SID of similar to 100-fmol amounts of model peptides HLGLAR (m/z 666.8), gramicidin S (m/z 1142.5), and bovine insulin b chain (m/z 3495.5) was accomplished using hydrocarbon-coated gold grids and similar to 20-eV collision energies, The current version of the instrument achieves a mobility resolution of similar to 20 and TOF mass resolution better than 200. Peptide sequences of four peptides from a tryptic digest of cytochrome c (similar to1 pmol deposited) were obtained. The advantage of IM-SID-o-TOF-MS is that a single experiment can be used to simultaneously measure the molecular weights of the tryptic peptide fragments (e.g,, peptide mass mapping) and partial sequence analysis, (e.g,, real-time tandem mass spectrometry.).