Sensitive detection of charge derivatized peptides at the attomole level using nano-LC-ESI–MRM analysis

•A nano-LC-ESI–MRM was applied for the sensitive analysis of QAS-tagged peptides.•Distinct a and b ion type series are presented for charge derivatized peptide.•Protonated peptides were analyzed at the pico- and femtomole concentration.•QAS derivatization increases the detection sensitivity 10–1000 times.

The detection sensitivity of peptides in the form of quaternary ammonium salts at the N-terminus was analyzed using liquid chromatography/electrospray ionization tandem mass spectrometry. The derivatization, efficiently prepared by the solid phase synthesis, achieved subfemtomole to attomole levels of peptide detection by measurement in the multiple reaction monitoring mode. The presented methodology creates a new possibility for analysis of trace amounts of peptides and other compounds.

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