title: Formation of odd-electron product ions in collision-induced fragmentation of electrospray-generated protonated cathinone derivatives: aryl α-primary amino ketones.
abstract: BACKGROUND
  Modification of the even-electron rule for fragmentation reactions of protonated molecules (even electron ions) may be necessary to interpret the liquid chromatography/mass spectrometry (LC/MS) spectra of aryl α-primary amino ketones as new designer drugs.
  
  
  METHODS
  Collision-induced fragmentation of 38 protonated cathinone derivatives generated by electrospray ionisation (ESI) was examined by hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MS).
  
  
  RESULTS
  Q-TOF MS revealed that odd-electron product ions are often formed by collision-induced dissociation (CID) of protonated aryl α-primary amino ketones, contradicting the even-electron rule. Radical cations were among the most characteristic and most abundant ions in the CID-MS/MS product spectra, and were usually represented by basic peaks in the spectra.
  
  
  CONCLUSIONS
  To help elucidate the correct structures of new aryl α-primary amino ketone drugs by LC/MS/MS, it is essential to include odd-electron product ions in the data interpretation rules. Even and odd numbers of valence electrons in the product ions should be allowed in data interpretation.
authors.affiliation: Chemistry Department, The John Paul II Catholic University of Lublin, al. Krasnicka 102, 20-718 Lublin, Poland. efornal@kul.lublin.pl
authors.forename: Emilia
authors.initials: E
authors.lastname: Fornal
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D015198:Designer Drugs / Q000737:chemistry*; D004583:Electrons; D007477:Ions / Q000737:chemistry*; D007659:Ketones; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000470:Alkaloids; D015198:Designer Drugs; D007477:Ions; D007659:Ketones; D011522:Protons; C023665:cathinone