An aerodynamic assisted miniature mass spectrometer for enhanced volatile sample analysis

Area of Science:

• Analytical Chemistry
• Instrument Development
• Environmental Science

Background:

• Miniature mass spectrometers with continuous atmospheric pressure interfaces (CAPI) are effective for non-volatile samples.
• Previous designs exhibited low sensitivity for volatile samples due to diffusion effects in the CAPI, especially with atmospheric pressure chemical ionization (APCI).

Purpose of the Study:

• To enhance the detection sensitivity of miniature mass spectrometers for volatile samples.
• To enable real-time chemical source tracing and remote sensing applications.

Main Methods:

• Designed and integrated an in-vacuum plasma ionization source into the miniature mass spectrometer system.
• Minimized ion transfer loss by performing ionization in the first vacuum stage.
• Developed an aerodynamic sampling method for directional sample transfer in open environments.

Main Results:

• Achieved detection sensitivities in the tens of parts per billion by volume (ppbv) for volatile samples, a significant improvement over previous ppmv levels.
• Demonstrated proof-of-concept for chemical source tracing in an indoor environment.
• Enabled remote chemical source sensing at distances exceeding two meters using the aerodynamic sampling method.

Conclusions:

• The in-vacuum plasma ionization source effectively overcomes CAPI limitations, enhancing sensitivity for volatile compound analysis.
• The integrated system and aerodynamic sampling method facilitate practical applications like environmental monitoring and source tracing.
• The aerodynamic sampling technique offers broader applicability to other mass spectrometry instruments for improved open-environment sampling.