2D-Molybdenum Disulfide-Derived Ion Source for Mass Spectrometry

Area of Science:

• Materials Science
• Analytical Chemistry
• Energy Harvesting

Background:

• Traditional mass spectrometry relies on external energy sources for ion formation.
• Nanostructured materials offer potential for novel energy generation and analytical applications.
• Developing self-powered analytical devices is a key goal in miniaturized sensing.

Purpose of the Study:

• To develop a new ambient soft ionization method for mass spectrometry.
• To utilize the electrokinetic effect at a liquid-solid interface for energy generation.
• To demonstrate the application of this method in detecting analytes and sensing alcohol.

Main Methods:

• Fabrication of a 2D-molybdenum disulfide (MoS₂) nanosheet surface.
• Development of a streaming ionization technique by flowing protic solvents over the MoS₂ surface.
• Characterization of current generation and analyte detection using mass spectrometry.
• Testing the device as a self-energized breath alcohol sensor.

Main Results:

• Achieved a record current generation of 1.3 A/m² using MoS₂ nanosheets and protic solvents.
• Successfully ionized and detected weakly bound ion clusters and uric acid in urine.
• Demonstrated a self-powered breath alcohol sensor capable of detecting 3% alcohol concentration.

Conclusions:

• Streaming ionization using 2D-MoS₂ offers a sustainable and energy-efficient method for mass spectrometry.
• The electrokinetic effect at the liquid-solid interface is a viable mechanism for generating usable current.
• This technology holds promise for developing portable, self-powered analytical sensors.