IR-MALDESI method optimization based on time-resolved measurement of ion yields

Area of Science:

• Mass Spectrometry Imaging
• Analytical Chemistry
• Biomedical Research

Background:

• Mass spectrometry imaging (MSI) typically analyzes complex samples without prior separation.
• Ion trapping in MSI can limit dynamic range due to ion trap capacity.
• Accurate timing is crucial for minimizing unwanted ions and maximizing analyte signals.

Purpose of the Study:

• To develop and demonstrate a method for synchronizing infrared laser ablation with ion collection.
• To optimize ion accumulation timing for improved signal-to-noise ratio in MSI.
• To enhance data quality in MSI experiments by controlling ion injection timing.

Main Methods:

• Utilized a Q Exactive Plus mass spectrometer for analysis.
• Implemented a method for synchronizing infrared laser ablation with electrospray post-ionization.
• Measured ion accumulation at fixed time points post-ablation.
• Conducted model imaging experiments using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDI).

Main Results:

• Achieved synchronicity between laser ablation and ion collection.
• Identified optimal injection time as the minimum duration to capture ions from the last laser pulse.
• Demonstrated a doubling or greater increase in target ion abundances compared to previous methods.
• Showcased improved data quality for lipid species in mouse liver tissue.

Conclusions:

• Precise timing control between laser ablation and ion collection is critical for MSI.
• The developed synchronization method significantly enhances analyte signal detection.
• Optimized timing strategies improve the dynamic range and data quality in mass spectrometry imaging.