A neutralization-reionization scheme for tandem mass spectrometry has been developed which uses proton-transfer rather than electron-transfer reactions. The neutralization reaction is an endothermic transfer of a proton from protonated peptides to ammonia carried out at beam energies close to threshold. The ammonia collision gas also serves as a reagent gas in a collision chamber that is also a chemical ionization source. As the kinetic energies of neutralized molecules are reduced by additional collisions, they are reprotonated in the same chamber by the reverse, exothermic reaction. The method has the advantages that the neutralization and reionization reactions can be carried out in a single chamber, that proton-transfer reactions are compatable with the protonated species produced by soft ionization techniques, and that additional fragmentation is observed. The method is referred to as neutralization-Chemical reionization mass spectrometry (NCRMS).
ASJC Scopus subject areas
- Colloid and Surface Chemistry