Molecule-specific imaging with mass spectrometry and a buckminsterfullerene probe: application to characterizing...

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Solid-phase synthesis is crucial for peptide combinatorial libraries.
• Characterizing diverse molecules on polymer supports presents analytical challenges.
• Conventional atomic ion beams have limitations in molecular desorption and imaging.

Purpose of the Study:

• To develop and evaluate a novel buckminsterfullerene (C(60)) primary ion beam for time-of-flight secondary ion mass spectrometry (TOF-SIMS).
• To assess the C(60) ion beam's capability for molecule-specific imaging of resin particles in peptide synthesis.
• To compare the performance of C(60) ion beams with atomic ion beams for enhanced molecular characterization.

Main Methods:

• Utilized a newly developed C(60) primary ion beam TOF-SIMS system.
• Focused the C(60) ion beam to a 1.5 micrometer spot size for high-resolution imaging.
• Analyzed small peptide libraries synthesized on polymer resin particles.
• Investigated energy dissipation and charge buildup on different substrates.

Main Results:

• Achieved a >3 orders of magnitude enhancement in the useful yield of molecular ions compared to atomic ion beams.
• Demonstrated efficient desorption of small peptides from polymer surfaces, with reduced impact on harder substrates.
• Observed significantly reduced surface charging on insulating polymer beads.
• Successfully assayed the surface composition of 100-micrometer polymer beads at a rate of up to 10 particles/s.

Conclusions:

• The C(60) primary ion beam TOF-SIMS is a powerful tool for rapid, molecule-specific analysis of peptide libraries.
• This technology offers significant advantages in sensitivity, efficiency, and reduced sample preparation for high-throughput screening.
• The findings open new avenues for characterizing diverse molecular arrays on various substrates.