The influence of structural features on facile McLafferty-type, even-electron rearrangements in tandem mass spectra of carboxylate anions.
In contrast to the well-described McLafferty rearrangement in odd-electron cations, relatively little has been reported on comparable rearrangements in even-electron ions, especially negative ions. This work reports a systematic study using tandem mass spectrometry (MS/MS) fragment ion spectra of carboxylate anions having a suitably acidic proton in the gamma position. The rearrangement process was studied in both ion trap and triple quadrupole mass spectrometers; characteristic enolate anions and stable neutral products were formed at low collision energies. The process has diagnostic and analytical potential in, for example, the analysis of peptides having C-terminal serine residues and of 3-hydroxy- or 3-aminocarboxylic acids in complex mixtures.
Grossert
J Stuart
JS
Department of Chemistry, Dalhousie University, Halifax, NS, Canada B3H 4J3.
Cook
Matthew C
MC
White
Robert L
RL
D000179:Acrylates / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry; D004583:Electrons; D007553:Isotope Labeling; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
D000179:Acrylates; D002264:Carboxylic Acids; D011522:Protons; D003903:Deuterium