To ensure detection, the QMS used a secondary electron multiplier detector with an electron ionizing (EI) filament set to 70 V. The fragmentation of FeCp2 was collected, both in scanning (SCAN) and multiple ion detection (MID) sampling modes. The QMS sampling was performed, using either a continuous flow of precursor and constant plasma discharge, or by time-resolving the precursor introduction and the plasma discharge. The mass-to-charge ratios (m/z) were set between m/z = 1 and m/z = 200.