Hydrogen-Assisted Photoionization and Its Use in Promoting Mass Spectrometry Analysis of VOCs

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chemical Physics

Background:

• Photoionization (PI) coupled with mass spectrometry (MS) is used for direct analysis of volatile organic compounds (VOCs).
• Conventional PI-MS suffers from low ion yields due to limited ultraviolet lamp intensity.

Purpose of the Study:

• To develop a hydrogen-assisted photoionization (HAPI) strategy to enhance ion yields for VOC analysis.
• To integrate HAPI into a miniature ion trap mass spectrometer.

Main Methods:

• Introduction of hydrogen as a buffer gas to facilitate both photoionization and ion trap operation.
• Development and integration of HAPI into a miniature ion trap mass spectrometer.
• Investigation of the photochemical processes involved in HAPI.

Main Results:

• Achieved ion yields up to 2 orders of magnitude higher than conventional PI-MS.
• Demonstrated low hydrogen consumption (less than 100 μL per analysis).
• Confirmed the generation of protonated ions, indicating a specific photochemical process.

Conclusions:

• HAPI significantly enhances ion yields for VOC analysis via mass spectrometry.
• The HAPI technique is versatile and practical for detecting various VOCs and plant volatiles.
• The developed method offers a substantial improvement over traditional PI-MS.