Figure 2.

Abundance ratio histogram. We calculated the “abundance ratio” as the sum of the relative abundance values of the m/z peaks matching the ordered peptide divided by the sum of the relative abundance values of all m/z peaks observed in the MS1 spectrum. We considered MS1 spectra with an abundance ratio <50% (red line) as indicative of problematic (or failed) syntheses and MS1 spectra with an abundance ratio >50% as successful. The MS1 spectra for 87% of the analyzed peptides met the abundance ratio threshold of >50% and were considered as successful syntheses.