Mass recalibration for desorption electrospray ionization mass spectrometry imaging using endogenous reference ions

Area of Science:

• Analytical Chemistry
• Biomedical Imaging

Background:

• Mass spectrometry imaging (MSI) generates large datasets with thousands of mass spectra.
• Instrument calibration can drift during acquisition, leading to significant mass errors.
• These errors hinder data interpretation and affect spatial distribution analysis.

Purpose of the Study:

• To develop a post-acquisition computational method for mass recalibration in MSI.
• To address mass drift issues in desorption electrospray ionization MSI (DESI-MSI).

Main Methods:

• A computational approach utilizing known mass-to-charge ratios of common molecules.
• Testing on time-of-flight and Orbitrap mass analyzers coupled with DESI.

Main Results:

• Reduced observed mass drift by up to 60 ppm in biological samples.
• Improved molecular annotation accuracy.
• Enhanced spatial distribution quality of detected ions.

Conclusions:

• The method provides robust and accurate post-acquisition mass recalibration for DESI-MSI.
• Increases the reliability of molecular assignment and overall data quality.