title: Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry.
abstract: BACKGROUND
  For unambiguous identification of Chemical Weapons Convention (CWC)-related chemicals in environmental samples, the availability of mass spectra, interpretation skills and rapid microsynthesis of suspected chemicals are essential requirements. For the first time, the electron ionization single quadrupole and electrospray ionization tandem mass spectra of a series of O-alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates (Scheme 1, cpd 4) were studied for CWC verification purposes.
  
  
  METHODS
  O-Alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates were prepared through a microsynthetic method and were analyzed using electron ionization and electrospray ionization mass spectrometry with gas and liquid chromatography, respectively, as MS-inlet systems. General EI and ESI fragmentation pathways were proposed and discussed, and collision-induced dissociation studies of the protonated derivatives of these compounds were performed to confirm proposed fragment ion structures by analyzing mass spectra of deuterated analogs.
  
  
  RESULTS
  Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as McLafferty rearrangement, hydrogen rearrangement and a previously unknown intramolecular electrophilic aromatic substitution reaction.
  
  
  CONCLUSIONS
  The EI and ESI fragmentation routes of the synthesized compounds 4 were investigated with the aim of detecting and identifying CWC-related chemicals during on-site inspection and/or off-site analysis and toxic chemical destruction monitoring. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Chemistry, Semnan University, P.O. Box 35131, -19111, Semnan, Iran.|Defense Chemical Research Lab (DCRL), P.O. Box 31585, -1461, Karaj, Iran.
authors.forename: Seyed Esmaeil
authors.initials: SE
authors.lastname: Hosseini
authors.affiliation: Department of Science, Payame Noor University (PNU), P.O. Box 19395, -4697, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Saeidian
authors.affiliation: Department of Chemistry, Semnan University, P.O. Box 35131, -19111, Semnan, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Amozadeh
authors.affiliation: Defense Chemical Research Lab (DCRL), P.O. Box 31585, -1461, Karaj, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Naseri
authors.affiliation: Defense Chemical Research Lab (DCRL), P.O. Box 31585, -1461, Karaj, Iran.
authors.forename: Mehran
authors.initials: M
authors.lastname: Babri