1. German Cancer Research Center and HI-STEM gGmbH, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
2. SCIEX Germany GmbH, Landwehrstraße
54, 64293 Darmstadt, Germany
3. Department
of Chemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland