A multiple channel electrospray source used to detect highly reactive ketenes from a flow pyrolyzer

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Organic Chemistry

Background:

• Highly reactive pyrolytic products like ketenes are transient and difficult to detect.
• Conventional methods struggle with the direct analysis of these unstable intermediates.

Purpose of the Study:

• To develop and implement a method for the direct detection of protonated molecular ions of reactive pyrolytic ketenes.
• To characterize cyclopentadienylideneketene, cyclohexadienylideneketenimine, and acetylketene.

Main Methods:

• Utilized a flow pyrolyzer coupled with a multiple-channel electrospray mass spectrometry system.
• Introduced nitrogen gas to transfer pyrolytic ketenes into the central channel of the electrospray ionization source.
• Employed electrosprayed methanol with trifluoroacetic acid in outer channels for ionization.

Main Results:

• Successfully detected protonated molecular ions of cyclopentadienylideneketene, cyclohexadienylideneketenimine, and acetylketene.
• Demonstrated effective ionization of neutral ketenes via ion-molecule reactions and protonation facilitated by charged methanol droplets.

Conclusions:

• The integrated flow pyrolyzer and electrospray mass spectrometry system is effective for detecting highly reactive pyrolytic ketenes.
• This technique provides a new avenue for studying transient species in pyrolytic processes.