Permanent charge N-terminal peptide derivatization prior analysis by mass spectrometry has been primarily investigated to optimize detection sensitivity and sequencing efficiency. In particular, the simplification of the recorded MS/MS spectra for straightforward ion assignment is of utmost interest when de novo sequencing of peptides is required or extensive protein sequence coverage needed. Additionally, such N-terminal insertion, provided that isotope labels are used, is also intended to afford comparative quantitation data. Depending on the N-terminal chemical modification, the fixed charge is either triggering skeletal peptide bond cleavage, as expected for sequence assignment, or producing fragment ions that are only representing the charged group, which is completely inadequate for sequencing purposes but highly valuable for detection/quantitation purposes. Among all fixed charge reagents that have been investigated so far, we focused our interest on well-documented phosphonium and far less investigated pyridinium moieties as derivatization chemicals for mass spectrometry analyses. According to the structural peptide modification, we aimed at inducing specific predictable charge remote fragmentation (CRF) pathways upon low energy activation conditions, such as collision-induced and/or metastable dissociations available with any conventional ESI-QqTof and MALDI-Tof/Tof instruments, to be used for either efficient sequencing or sensitive peptide monitoring (detection/quantitation). All MS/MS behaviors recorded for the prepared N-terminal modified model peptides presenting a permanent positive phosphonium or pyridinium charge will be presented and discussed in the attempt to govern the dissociation pathways. Acetylation with commercially available tris(trimethoxyphenyl)phosphonium (TMPP) is known to trigger peptide backbone ruptures leading to abundant a-type sequence ions. Although it has been reported as a valuable proteogenomic method for systematic identific