Detection of Neutral CO Lost During Ionic Dissociation Using Atmospheric Pressure Thermal Dissociation Mass Spectrometry (APTD-MS)

Pengyi Zhao, Travis White, R. Graham Cooks, Qinghao Chen, Yong Liu, Hao Chen

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Elucidation of ion dissociation patterns is particularly important to structural analysis by mass spectrometry (MS). However, typically, only the charged fragments from an ion dissociation event are detected in tandem MS experiments; neutrals are not identified. In recent years, we have developed an atmospheric pressure thermal dissociation (APTD) technique that can be applied to dissociate ions at atmosphere pressure and thus provide one way to characterize neutral fragments. In this paper, we focus on the detection of neutral CO resulting from amino acid and peptide ion dissociation. In the first set of experiments, several protonated amino acids (e.g., + 1 ion of phenylalanine) were found to undergo loss of a neutral (s) of total mass 46 Da, a process leading to iminium ion formation. We successfully detected the neutral species CO by using a CO sensor, UV-Vis and MS analysis following selective CO trapping with a rhodium complex. The capture of CO from dissociation of protonated amino acids supports the assignment of the loss of 46 Da to neutral losses of CO and H 2 O, rather than loss of formaldehyde or dihydroxycarbene, other possible fragmentation pathways that have been subject of debate for a long time. In a second experiment, we used the APTD method in combination with the CO detection technique, to demonstrate the formation of CO in the conversion of b ions to a ions during peptide ion dissociations. These results showed the potential of APTD in the elucidation of ion dissociation mechanisms, using simple home-built apparatus. [Figure not available: see fulltext.].

Original languageEnglish (US)
Pages (from-to)2317-2326
Number of pages10
JournalJournal of the American Society for Mass Spectrometry
Issue number12
StatePublished - Dec 1 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Spectroscopy


  • Carbon monoxide, peptide and amino acid
  • Mass spectrometry
  • Neutral fragment detection


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