All-solid-state deep ultraviolet laser for single-photon ionization mass spectrometry.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Laser Physics

Background:

• Time-of-flight mass spectrometry (TOF-MS) is a powerful analytical technique.
• Single-photon ionization (SPI) offers soft ionization for reduced fragmentation.
• Deep ultraviolet (DUV) lasers provide high photon energies for ionization.

Purpose of the Study:

• To develop a novel reflectron time-of-flight mass spectrometer.
• To utilize an all-solid-state deep ultraviolet (DUV) laser system for single-photon ionization.
• To achieve fragmentation-free ionization of chemicals, particularly organic compounds.

Main Methods:

• Developed a DUV laser system (177.3 nm) using a novel nonlinear optical crystal (KBe2BO3F2) and second harmonic generation.
• Integrated the DUV laser with pulsed nanospray and thermal evaporation sources for supersonic expansion molecular beams.
• Employed reflectron time-of-flight mass spectrometry for analysis.

Main Results:

• Achieved DUV laser generation with a 177.3-nm wavelength, 15.5-ps pulse duration, and ~15 μJ pulse energy.
• Demonstrated fragmentation-free single-photon ionization of aromatic amine compounds.
• Successfully identified chemicals from an unknown mixture using the developed DUV-SPI-MS instrument.

Conclusions:

• The developed DUV-SPI-MS instrument enables sensitive and selective analysis of organic compounds.
• The novel all-solid-state DUV laser system is effective for fragmentation-free ionization.
• This technique has significant potential for identifying chemicals in complex mixtures.