Simultaneous on-line vacuum single- and multi-photon ionization on an orthogonal acceleration time-of-flight mass...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Spectroscopy

Background:

• Orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry offers superior mass accuracy and resolving power compared to conventional TOF instruments.
• Continuous ion sources are preferred for high duty cycles, while pulsed sources require high repetition rates for broad mass range coverage.
• Combining different ionization techniques can provide complementary information for comprehensive analysis.

Purpose of the Study:

• To develop and demonstrate a novel system integrating a continuous single-photon ionization (SPI) source and a pulsed resonance enhanced multi-photon ionization (REMPI) source with an oa-TOF mass spectrometer.
• To showcase the simultaneous operation of SPI and REMPI for comprehensive mass spectral analysis without ion storage.
• To evaluate the system's robustness and applicability in real-world industrial environments.

Main Methods:

• A deuterium lamp single-photon ionization (SPI) source was coupled with a pulsed 2000 Hz excimer (KrF) laser for resonance enhanced multi-photon ionization (REMPI).
• The SPI and REMPI sources were integrated with an orthogonal acceleration time-of-flight (oa-TOF) mass spectrometer, enabling simultaneous data acquisition.
• A second data acquisition card was implemented for independent storage of SPI and REMPI data, allowing for targeted analysis and modified sensitivities.

Main Results:

• The combined SPI/REMPI-oa-TOF system successfully acquired complementary data from both ionization methods simultaneously.
• Demonstrated applications included on-line monitoring of coffee roast gas emissions and e-cigarette vapor, as well as gas chromatography (GC) measurements.
• The system exhibited high robustness in industrial settings, providing a higher density of information per measurement and saving time and resources.

Conclusions:

• The developed SPI/REMPI-oa-TOF system represents a significant advancement in mass spectrometry, offering a versatile platform for complex sample analysis.
• The simultaneous use of soft broadband (SPI) and selective soft (REMPI) ionization techniques enables comprehensive mass range coverage and targeted monitoring.
• This robust and efficient system provides valuable complementary information, enhancing analytical capabilities for diverse applications.