ECD-like peptide fragmentation at atmospheric pressure

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Traditional peptide fragmentation methods often require vacuum conditions.
• Electron capture dissociation (ECD) is effective but typically performed under vacuum.
• Atmospheric pressure ionization (API) techniques are crucial for analyzing complex biological samples.

Purpose of the Study:

• To investigate peptide fragmentation using gas discharge products at atmospheric pressure.
• To characterize the fragmentation mechanism and identify resulting ion types.
• To assess the applicability of this method for analyzing modified peptides and mixtures.

Main Methods:

• Utilized ion mobility separation coupled with a fragmentation cell and linear ion trap mass spectrometer.
• Employed gas discharge at atmospheric pressure for ion interaction.
• Analyzed fragmentation spectra and varied discharge parameters (gas type, polarity).

Main Results:

• Fragmentation spectra were dominated by c-type ions, characteristic of electron capture dissociation.
• Fragmentation was confirmed to proceed via free electron capture.
• A phosphorylated peptide yielded c-type fragments retaining the phosphorylation group.
• Demonstrated feasibility of MS/MS-like experiments on peptide mixtures using prior ion mobility separation.

Conclusions:

• Atmospheric pressure electron capture dissociation is a viable method for peptide fragmentation.
• This technique preserves post-translational modifications like phosphorylation.
• The integration with ion mobility separation allows for complex mixture analysis at atmospheric pressure.