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. 2019 Dec 9;14(12):e0226012. doi: 10.1371/journal.pone.0226012

Fig 2. Noise level, number of detected peaks and peak density.

Fig 2

A) Noise level in the spectra, as a function of the number of shots. Noise is estimated as described in “Materials and methods” and shown for RS1 obtained on the Bruker Ultraflextreme (purple) and for RS2 on the SimulTOF100 (green). The lines show the expected slope of -1/2 and are shifted by instrument dependent offsets. B) Number of detected peaks for a fixed SNR cutoff, as a function of the number of laser shots for RS2 on the SimulTOF (SNR = 10 (dark blue circles), 20 (light blue triangles), 40 (green squares), 60 (red diamonds)). C) Density of detected peaks at a SNR cut-off of 10 obtained by counting the number of peaks in equal-width m/z bins (the m/z range from 3200 to 30000 Da was divided into 60 bins), for the 100 million shot spectrum as a function of m/z. The dotted blue line is a smoothed version of this density, and the red line is proportional to the inverse peak width estimated from several most prominent peaks in the spectrum.