High-Spatial Resolution Atmospheric Pressure Mass Spectrometry Imaging Using Fiber Probe Laser Ablation-Dielectric Barrier Discharge Ionization

Atmospheric pressure mass spectrometry imaging (AP-MSI) is a powerful tool in many fields; however, there are still some difficulties to achieve high spatial resolution for AP-MSI, one of them being the need for a small ablation crater. Here, a fiber probe laser ablation (FPLA) system is introduced that uses an etched optical fiber with a sharp tip (o.d. 200 nm) to deliver ablation laser pulses to a sample surface to ablate materials with high spatial resolution. The tip-to-sample distance was adjusted to similar to 10 mu m using a micro-actuator having a stepping motor with submicron accuracy. The laser-ablated neutrals were postionized using a home-built in-line dielectric barrier discharge source, which can be interfaced to any mass spectrometer with an AP interface. Using MSI on a standard sample with a striped pattern and sections of fingernails treated with the drug methyl green zinc chloride salt, a FPLA-DBDI-MSI spatial resolution of approximate to 5 mu m was demonstrated.

Automated summary

Atmospheric pressure mass spectrometry imaging (AP-MSI) is a powerful tool, but achieving high spatial resolution remains a challenge due to the need for a small ablation crater. A fiber probe laser ablation (FPLA) system was introduced to address this issue by using an optical fiber with a sharp tip to deliver ablation laser pulses with high spatial resolution. This system demonstrated a spatial resolution of approximately 5 μm, showing promising results for future applications.