Research Article

Journal of The American Society for Mass Spectrometry

, Volume 24, Issue 4, pp 602-608

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Single-Photon Ionization of Organic Molecules Beyond 10 kDa

  • Philipp SchmidAffiliated withUniversity of Vienna, Faculty of Physics
  • , Frederik StöhrAffiliated withUniversity of Vienna, Faculty of Physics
  • , Markus ArndtAffiliated withUniversity of Vienna, Faculty of Physics Email author 
  • , Jens TüxenAffiliated withDepartment of Chemistry, University of Basel
  • , Marcel MayorAffiliated withDepartment of Chemistry, University of BaselKarlsruhe Institute of Technology (KIT), Institute of Nanotechnology


The volatilization and soft ionization of complex neutral macromolecules at low energies has remained an outstanding challenge for several decades [1]. Most volatilization techniques in mass spectrometry produce ions already in the source and most of them lead to particle velocities in excess of several hundred meters per second. For many macromolecules, post-ionization is inefficient since electronic or optical excitations can be followed by competing non-ionizing internal conversion, electron recapture, or fragmentation processes. Here, we explore the laser-assisted volatilization of neutral perfluoroalkyl-functionalized tetraphenylporphyrins as well as their single-photon ionization using vacuum ultraviolet (VUV) light at 157 nm. A systematic investigation of the ionization curves allows us to determine the molecular velocity distribution and ionization cross sections. We demonstrate the detection of single photon ionized intact organic molecules in excess of 10 kDa from a slow molecular beam.

Key words

Single-photon ionization VUV ionization Slow molecular beams Tailored porphyrin derivatives