Energy Resolved Mass Spectrometry of Dialkyl Methylphosphonates with an Atmospheric Pressure Ionization Tandem Mass Spectrometer

✍ Scribed by Michael W. Wensing; A. Peter Snyder; Charles S. Harden

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 629 KB
• Volume: 10
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19960731)10:10<1259::aid-rcm646>3.0.co;2-7

✦ Synopsis

The dialkyl methylphosphonates: dimethyl methylphosphonate (DMMP), diethyl methylphosphonate (DEMP), diisopropyl methylphosphonate (DIMP), and isopropyl methyl methylphosphonate (IMMP) were characterized using atmospheric pressure chemical ionization energy resolved mass spectrometry (API-ERMS). API, a very soft ionization technique, is required for these compounds since they undergo very low energy rearrangements, and even methane-chemical ionization results in significant fragmentation. API-ERMS was used to characterize the above homologous series of compounds. This work shows that ERMS can supply much more information than conventional fixed energy tandem mass spectrometry (MSIMS), by providing the energy at which product ions are formed in addition to the mass-to-charge ratio and intensity data provided by MS/MS. From these results, dissociation pathways were proposed and compared with those produced by other workers. In addition, it was shown that the dissociation pathways of IMMP could be predicted solely based on energetic considerations and the knowledge of the dissociation pathways of DIMP and DEMP. This is the first work to provide the dissociation pathways of IMMP.