Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry by Matrix-Assisted Laser Desorption...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Proteomics

Background:

• Two-dimensional Fourier transform ion cyclotron resonance (2D FTICR) mass spectrometry is an advanced data-independent acquisition technique.
• Current 2D FTICR methods predominantly use electrospray ionization (ESI).
• Matrix-assisted laser desorption ionization (MALDI) has been limited by inconsistent ion generation from dried droplet preparations.

Purpose of the Study:

• To adapt matrix-assisted laser desorption ionization (MALDI) for use as an ionization source in two-dimensional Fourier transform ion cyclotron resonance (2D FTICR) mass spectrometry.
• To develop a method for creating a homogeneous sample surface suitable for MALDI-based 2D FTICR.
• To evaluate the quality and structural information content of 2D FTICR spectra generated using MALDI.

Main Methods:

• Utilized pneumatic spray techniques, commonly employed in mass spectrometry imaging, to deposit a homogeneous mixture of peptides and matrix onto a glass slide.
• Employed an HTX pneumatic sprayer for consistent surface preparation.
• Applied matrix-assisted laser desorption ionization (MALDI) to ionize the prepared peptide mixture for analysis with a standard 2D FTICR pulse sequence.

Main Results:

• Successfully generated two-dimensional (2D) mass spectra using MALDI as the ionization source for 2D FTICR.
• The resulting 2D MALDI FTICR spectra provided structural information comparable to traditional one-dimensional (1D) experiments.
• Observed artifacts in the 2D MALDI spectra were consistent with those typically seen in 2D ESI spectra, indicating good data quality.

Conclusions:

• Pneumatic spray deposition coupled with MALDI provides a viable and consistent method for ionizing samples in 2D FTICR mass spectrometry.
• This approach expands the applicability of 2D FTICR, offering an alternative to ESI for specific sample types or experimental needs.
• The developed method yields high-quality data, comparable to established techniques, for peptide analysis and structural elucidation.