Coupling high-pressure MALDI with ion mobility/orthogonal time-of-flight mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biophysical Chemistry

Background:

• Ion mobility spectrometry coupled with mass spectrometry (IM-MS) offers enhanced separation capabilities for complex mixtures.
• High-pressure sources in IM-MS can improve ion manipulation and separation efficiency.

Purpose of the Study:

• To design and test a new ion mobility/time-of-flight mass spectrometer prototype.
• To evaluate the instrument's performance in separating and identifying peptide mixtures.

Main Methods:

• Development of a prototype instrument integrating a high-pressure matrix-assisted laser desorption/ionization (MALDI) source with an ion mobility drift cell and a time-of-flight mass spectrometer.
• Operation at source/drift cell pressures of 1-10 Torr helium.
• Separation and mass identification of a simple tripeptide mixture and a tryptic digest of a protein.

Main Results:

• The prototype achieved a mobility resolution of approximately 25.
• A time-of-flight mass spectrometer with a mass resolution up to 200 was used for ion identification.
• Successful separation and mass identification of singly protonated species in a tripeptide mixture.
• Demonstrated ability to separate peptide mixtures, comparable to high-vacuum time-of-flight instruments.

Conclusions:

• The developed high-pressure MALDI-IM-TOF instrument is capable of separating and identifying peptide mixtures.
• This technology provides a viable alternative for peptide analysis, complementing existing high-vacuum mass spectrometry techniques.