Stick spectrum of the merged data set of 380 peak-lists. The black vertical lines represent peaks calibrated using the TPS and MST method. Their height equals their intensity. Green line – average mass of all peaks in the region 842 – 843Da (A) and 2210.5 – 2211.6Da (B). The orange vertical lines represent the average mass ±, the standard deviation of the peak masses in each region. Magenta line – density of peak-masses.