Quantitative transfer of polar analytes on a solid surface to a liquid matrix in MALDI profiling

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biochemistry

Background:

• Matrix-assisted laser desorption ionization (MALDI) is a key technique for specimen profiling.
• Quantitative analysis in MALDI can be limited by solvent evaporation during analyte extraction.
• Solid matrices pose challenges for complete and quantitative analyte extraction.

Purpose of the Study:

• To investigate the quantitative extraction of analytes using a liquid matrix in MALDI.
• To determine the optimal conditions for maximizing analyte recovery during MALDI profiling.
• To compare the efficiency of liquid matrices versus solid matrices for analyte extraction.

Main Methods:

• Controlled experiments varying analyte circle radius (rA), matrix solution drop radius (rD), and liquid matrix radius (rM) after solvent evaporation.
• Preparation of three sample cases (A, B, C) based on the relative radii.
• Quantitative analysis of analyte amounts within the matrix layer using MALDI.

Main Results:

• Case A (rA, rD < rM): Analyte amount matched prepared amount within the analyte circle.
• Case B (rD ≤ rM < rA): Analyte amount matched the amount within the matrix circle, indicating precise transfer.
• Case C (rM < rD < rA): Analyte amount exceeded that within the matrix circle due to solvent-mediated dissolution of external analytes.

Conclusions:

• Liquid matrices facilitate more quantitative analyte extraction in MALDI profiling compared to solid matrices.
• The spatial relationship between analyte, matrix solution, and liquid matrix significantly impacts extraction efficiency.
• Liquid matrices offer improved control and accuracy for MALDI-based quantitative analysis.