FTICR-MS imaging

Analytical methods are pursued by the Macromolecular Ion Physics group to determine the identity and location of biomolecules down to the subcellular (micrometer) level. Available mass spectrometric imaging methods either compromise localization accuracy or identification accuracy in their analysis of surface biomolecules. MALDI-FTICR-MS is developed for the spatially resolved mass analysis of rat brain tissue with the aim to optimize protein identification by the high mass accuracy and online MS/MS capabilities of the technique. Mass accuracies down to 1 ppm were obtained in the direct MALDI-analysis of the tissue together with a spatial resolution of 200 micrometer. The spatial distributions of biomolecules differing in mass by less than 0.1 Da could be resolved, and are shown to differ significantly. Online MS/MS analysis of selected ions was employed for endogenous peptide identification.