Derivatization with the Introduction of a Fixed Charge for the Analysis of Low-Molecular-Weight Oligopeptides by MALDI Mass Spectrometry

The previously described derivatization approach based on the interaction of compounds with the primary amino group and the tris(2,6-dimethoxyphenyl)methyl cation is tested and proposed for increasing the efficiency (desorption) of the ionization of low-molecular-weight oligopeptides under MALDI conditions. The results obtained showed that the use of the method ensures the achievement of an increase in the yield of ion, and a large increment of the introduced group outputs the target signals from the noisy low-molecular-weight region of the mass spectrum. The study of the main fragmentation pathways of the derivatives under collision-induced dissociation ensure the identification of a series of ions suitable for establishing the amino acid sequence of peptides.