Online MALDI-TOF MS using an aerodynamic lens assembly as a direct deposition interface

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Particle Analysis

Background:

• Matrix-assisted laser desorption/ionization (MALDI) is a key technique for analyzing biomolecules and polymers.
• Online analysis of suspended particles using MALDI presents challenges in sample introduction and deposition.
• Existing methods may require complex sample preparation or lack direct in situ capabilities.

Purpose of the Study:

• To develop and demonstrate a novel aerodynamic lens assembly for direct particle transport and in situ MALDI analysis.
• To provide an alternative method for online MALDI analysis of suspended particles.
• To evaluate the feasibility of analyzing polymer particles using this new system.

Main Methods:

• An aerodynamic lens assembly was designed to focus sampled particles into a beam.
• Particles were directly deposited onto a target plate for in situ analysis.
• A 266 nm laser was used for desorption/ionization at a 50-degree incidence angle.
• Ions were detected using a reflectron mass spectrometer with delayed ion extraction and ion gating.

Main Results:

• The system successfully transported and deposited matrix/analyte/salt-contained particles.
• MALDI-TOF mass spectra were obtained for poly(ethylene glycol) (PEG) 1000, 2000, and 4000 particles.
• Initial experiments confirmed the capability of the design for online MALDI analysis.

Conclusions:

• The developed aerodynamic lens assembly enables direct particle deposition for in situ MALDI analysis.
• This design offers a promising new approach for online analysis of suspended particles.
• The system demonstrates potential for analyzing various particle types in real-time applications.