Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography.

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chromatography

Background:

• Direct surface analysis is crucial for various chemical and biological applications.
• Traditional methods for visualizing compounds on thin-layer chromatography (TLC) plates often require staining or charring, which can be destructive or time-consuming.
• Developing advanced analytical techniques for direct, non-destructive analysis of separated compounds on TLC plates is essential.

Purpose of the Study:

• To introduce and evaluate the Molecular Ionization-Desorption Analysis Source (MIDAS) as a novel platform for direct surface analysis.
• To demonstrate the utility of MIDAS for the direct analysis and identification of compounds separated on TLC plates.
• To showcase the capabilities of MIDAS in both qualitative and quantitative analysis of substances directly from TLC.

Main Methods:

• Development of a Molecular Ionization-Desorption Analysis Source (MIDAS), a desorption atmospheric pressure chemical ionization (DAPCI) type source for mass spectrometry.
• Direct analysis of thin-layer chromatography (TLC) plates using MIDAS for mass spectrometry.
• Detection and identification of amino acids and active ingredients from an analgesic tablet separated on TLC plates.
• Utilizing positive and negative ion modes for comprehensive compound detection.
• Quantitative analysis of caffeine spots on TLC plates with varying concentrations.

Main Results:

• MIDAS successfully detected and identified amino acids directly from TLC plates, bypassing the need for staining.
• All active ingredients from an analgesic tablet, separated on a TLC plate, were identified using MIDAS in both positive and negative ion modes.
• Retention factor (Rf) values were calculated using reference marks and ion chromatograms.
• Quantitative analysis demonstrated a linear relationship (R2 = 0.994) for caffeine spots ranging from 50 to 1000 ng, highlighting the device's quantitative capabilities.

Conclusions:

• MIDAS is a versatile, multi-functional platform for direct surface analysis, particularly effective for TLC plates.
• The developed MIDAS technology enables direct, label-free detection and identification of diverse compounds, including amino acids and pharmaceutical ingredients.
• MIDAS offers significant potential for advancing analytical methodologies in chromatography and mass spectrometry due to its qualitative and quantitative performance.