Precursor Off/Plasma On requires an analysis of the measured signal from the modified QCM. It is paramount to explore any potential interference due the electron current drawn from the plasma to the crystal, which could result in a perturbed measurement of the crystal resonant frequency. We therefore exposed the QCM to a continuous (Fig. ) and pulsed (Fig. ) flow of plasma electrons, without any flow of FeCp2 in the chamber. The plasma power was varied between 5 W and 20 W and the QCM bias voltage was maintained at +40 V. For all explored plasma powers, the measured frequency increases with increased plasma power. This is in line with the increased electron current through the surface. In a QCM, the change in areal mass density scales reversely with the oscillation frequency (∆𝑚/𝐴 ∝ -∆𝑓), implying that an event that appears to be a mass loss is expected when the plasma is ignited.