Heidelberg 2015 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 3: New Mass Spectrometric Methods and Technical Developments

MS 3.5: Vortrag

Montag, 23. März 2015, 18:00–18:15, PH/HS2

Delayed bunching of ions in multi-reflection time-of-flight mass separators — •M. Rosenbusch¹, S. Kemnitz², P. Luksch², G. Marx¹, R. Schneider¹, L. Schweikhard¹, and N. R. Wolf¹ — ¹Institut für Physik, Ernst-Moritz-Arndt-Universität, 17487 Greifswald — ²Institut für Informatik, Universität Rostock, 18095 Rostock

Multi-reflection time-of-flight mass separators (MR-ToF MS) consist of two electrostatic mirrors facing one another, which enable back-and-forth reflections of ions and thus provide a long flight path. In that way, mass resolving powers m/δ m exceeding 10⁵ can be reached in only tens of milliseconds [1]. However, in case of contaminating ions in large quantities from the ion source, the mass separation is often hindered due to the dominance of coulomb interactions [2]. In this contribution a technique is discussed, that allows to decrease the ion density during the major part of the trapping period in the MR-ToF MS, while later on still enabling a high-resolution mass separation. To this end, an ion bunch with a purposely broad time-of-flight (ToF) distribution is injected into the MR ToF MS and trapped isochronously (no ToF energy dispersion) for a duration of choice. Then, the ToF-energy dispersion of the system is modified by a fast switching of the electrostatic-mirror voltages for strong focusing during the next few reflections. Proof-of-principle experiments with isobaric ions will be reported.
[1] R. N. Wolf et al., Int. J. Mass Spectrom. 349-350, 123-133 (2013)
[2] M. Rosenbusch et al., AIP Conf. Proc. 1521, 53 (2013)