N-terminal chemical derivatization of peptides with 4-formyl-benzenesulfonic acid and electrospray positive and negative tandem mass spectrometry with high abundance of b-ion series.

The FBSA derivatization and de novo sequencing approach outlined here provides a reliable method for accurate peptide sequence assignment. Increased production of the b-ions in positive and negative ion mode greatly improves peak assignment and thus enables accurate sequence reconstruction. Implementation of the named methodology would improve the quality of de novo sequencing data and reduce the number of misinterpreted spectra.