Laser Ablation Electrospray Ionization Achieves 5 μm Resolution Using a Microlensed Fiber

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Microscopy

Background:

• Conventional laser ablation electrospray ionization mass spectrometry (LA-ESI-MS) has limitations in spatial resolution for chemical mapping.
• There is a need for advanced imaging techniques to provide higher resolution chemical analysis of sample surfaces.

Purpose of the Study:

• To develop and demonstrate a new infrared laser-based imaging technique for high-resolution chemical mapping.
• To compare the spatial resolution of the new technique with conventional LA-ESI-MS.

Main Methods:

• A pulsed infrared (IR) laser (1064 nm) focused via a microlensed fiber desorbs analytes from a sample surface.
• Charged microdroplets capture desorbed analytes before mass spectrometry analysis.
• Sample surface translation generates a chemical map with 5 μm resolution.

Main Results:

• The developed technique achieved a spatial resolution of 5 μm.
• Chemical mapping of a parsnip root section demonstrated the technique's capability.
• The new imaging method showed approximately a 20-fold improvement in spatial resolution compared to conventional LA-ESI-MS.

Conclusions:

• The novel IR laser imaging technique offers significantly enhanced spatial resolution for chemical mapping.
• This advancement provides a powerful tool for detailed chemical analysis of biological and other sample surfaces.
• The technique shows promise for applications requiring high-resolution chemical imaging.