Surface Desorption Dielectric-Barrier Discharge Ionization Mass Spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Surface Science

Background:

• Dielectric-barrier discharge (DBD) is a versatile plasma source.
• Existing DBD methods can face limitations in ion transmission efficiency and spatial resolution for mass spectrometry.
• Developing advanced ionization techniques is crucial for sensitive molecular analysis and imaging.

Purpose of the Study:

• To develop a novel dielectric-barrier discharge ionization technique for mass spectrometry.
• To achieve high-efficiency ion transmission and high spatial resolution imaging.
• To investigate the operational parameters influencing sensitivity and spatial resolution.

Main Methods:

• Development of surface desorption dielectric-barrier discharge ionization (SDDBDI) using a tungsten nanotip and MS inlet as electrodes.
• Utilizing a coverslip as both sample plate and dielectric barrier for simplified configuration.
• Systematic investigation of operational parameters affecting sensitivity and spatial resolution.
• Demonstration of SDDBDI for analyzing amino acids, pharmaceuticals, biomarkers, fatty acids, and hormones.

Main Results:

• SDDBDI achieved high plasma density due to surface microdischarge generation.
• Analyte ions were directly guided into the MS inlet, enhancing ion transmission efficiency and sensitivity.
• Achieved limits of detection of 0.84 pmol for l-alanine and 0.18 pmol for metronidazole.
• Demonstrated a spatial resolution of 22 μm for cyclophosphamide pattern analysis.
• Successfully imaged a "T" character under ambient conditions.

Conclusions:

• SDDBDI is a simplified and effective mass spectrometry ionization technique.
• The method offers high-efficiency ion transmission, high sensitivity, and high spatial resolution.
• SDDBDI shows significant potential as a tool for mass spectrometry imaging applications.