The AMOLF Mass Microscope

Recently, we demonstrated a novel concept in imaging mass spectrometry using large area illumination and spatially resolved ion detection instead of spatially resolved ion generation, the so-called mass microscope approach. Since this is a true ion imaging methodology, the spatial resolution is no longer determined by the size of the desorption / ionisation probe (the laser spot), but rather by the quality of the ion optics and the detector. In a single laser shot intact biomolecules can be desorbed and ionized from a large area using the Matrix Assisted Desorption and Ionization (MALDI) or Secondary Ion Mass Spectrometry (SIMS) process. Inside the ion imaging Time-of-Flight mass spectrometer this results in a set of traveling molecular images that are separated based on the different velocities corresponding to the different molecular masses. In the current configuration this results in 600 nm small pixel sizes over an area of 200 micrometer independent of the ionization method used. Direct stigmatic imaging of biomolecules on the surface of histopathological tissue can visualize a multitude of biomolecules. The technique can, among others, be applied in biomedical studies and pharmacokinetics.