Single-Photon Ionization of Organic Molecules Beyond 10 kDa

Author(s): P. Schmid, F. Stöhr, M. Arndt, J. Tuexen, M. Mayor

Journal: Journal of the American Society for Mass Spectroscopy

Volume: 24

Page(s): 602-608

Year: 2013

DOI Number: 10.1007/s13361-012-0551-3

Link: Link to publication

Abstract:

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.

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