MALDI-MS Analysis of Carbohydrates Using Ionic Liquid Matrices: Insights Into Ionization Efficiency and Sample...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• Ionic liquids matrices (ILMs) offer advantages in MALDI-MS over crystalline matrices.
• ILMs improve desorption/ionization efficiency and sample homogeneity.

Purpose of the Study:

• To investigate specific ionic solid matrices (ISMs) and non-ionic solid matrices (NISMs) for low molecular weight (LMW) carbohydrate analysis.
• To explore the impact of modifying cationic components of acid-amine mixtures on MALDI-MS performance.

Main Methods:

• Synthesized and characterized novel mixed matrices by modifying classical acidic MALDI matrices with various aliphatic amines.
• Analyzed physical and morphological properties of the matrices.
• Employed MALDI mass spectrometry imaging (MSI) for analyte distribution assessment.
• Utilized UV-Vis absorption, diffuse reflectance, 1H-NMR, and LDI-MS to characterize matrix ionicity.

Main Results:

• Matrix efficiency in MALDI-MS was found to be independent of the ionic character of the solid matrices.
• Differences in desorption/ionization efficiency in acid-amine matrices may relate to the solid-state proximity of ionizable groups.
• A new chromophoric unit with potentially improved physicochemical properties for MALDI matrix function was suggested.
• Observed heterogeneity in all samples highlights challenges in achieving reproducible data.

Conclusions:

• The ionic character of solid matrices does not solely determine MALDI-MS efficiency for LMW carbohydrate analysis.
• Solid-state arrangement of ionizable groups is a critical factor influencing matrix performance.
• Further research is needed to overcome sample heterogeneity for reproducible MALDI-MS results.