A Novel Derivatization Method for Peptides to Increase Sensitivity and Backbone Fragmentation in Liquid Secondary-Ion Mass Spectra

Rapid Commun Mass Spectrom. 1992 Dec;6(12):747-52. doi: 10.1002/rcm.1290061207.


Derivatization is used to increase both negative-ion sensitivity and positive-ion sequence information in the liquid secondary-ion mass spectra (LSIMS) of a series of peptides. The derivatization method involves acylation with pentafluorobenzoyl fluoride in a single-step reaction, and the reaction mixture is applied directly to the probe tip for analysis. Acylation takes place at the unprotected N-terminus, tyrosine, and lysine. The derivatives exhibit increased signal-to-noise ratio for [M-H]- ions, especially where there is not already an acidic amino acid residue in the peptide. In positive-ion LSIMS, the N-terminal group acts to retain the charge at the N-terminus, simplifying the fragmentation by producing N-terminal fragment ions. It also increases positive-ion fragmentation, sometimes very dramatically, making sequence determination more straightforward. The simplicity of the process, together with the enhancements it provides, make this a generally useful method for obtaining peptide structural information.

MeSH terms

  • Amino Acid Sequence
  • Angiotensin III / analysis
  • Bradykinin / analysis
  • Chromatography, High Pressure Liquid
  • Enkephalin, Leucine / analysis
  • Gas Chromatography-Mass Spectrometry
  • Indicators and Reagents
  • Molecular Sequence Data
  • Peptides / isolation & purification*


  • Indicators and Reagents
  • Peptides
  • Angiotensin III
  • Enkephalin, Leucine
  • Bradykinin