Performance Evaluation of an EI&CI Dual Ionization TOFMS Hyphenated with a Flow Modulated GC×GC System

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chromatography

Background:

• Two-dimensional gas chromatography (GC×GC) coupled with mass spectrometry (MS) is a powerful technique for complex mixture analysis.
• Optimizing MS performance, including ionization techniques and acquisition speed, is crucial for effective GC×GC hyphenation.

Purpose of the Study:

• To evaluate the performance and compatibility of a dual-ionization TOFMS (EI and CI sources) with GC×GC.
• To investigate key performance metrics for GC×GC-MS hyphenation, including acquisition speed, ion source response, and EI/CI switching capabilities.
• To demonstrate the application of the developed system for analyzing real-world samples, such as traffic emissions.

Main Methods:

• A novel dual-ionization TOFMS system with parallel EI and CI sources was developed and coupled to a GC×GC system.
• Fast switching ion optics enabled 100 Hz switching between EI and CI spectra.
• The system's performance was assessed by investigating acquisition speed, ion source response, GC transfer efficiency, and data alignment.
• Spectra quality was compared to a standard single quadrupole MS setup.
• High flow ratios were utilized to enhance CI sensitivity.

Main Results:

• The dual-ionization TOFMS demonstrated effective hyphenation with GC×GC, featuring fast EI/CI switching at 100 Hz.
• Significantly improved CI sensitivity (up to 37-fold increase) was achieved by optimizing flow ratios to the CI source.
• Spectra quality was maintained while achieving high acquisition speeds, crucial for GC×GC.
• The system successfully analyzed thermal desorption GC×GC-EI&CI-TOFMS of traffic emission samples.

Conclusions:

• The developed dual-ionization TOFMS is highly compatible with GC×GC, offering enhanced sensitivity and rapid switching between EI and CI modes.
• This advanced analytical system provides a robust platform for detailed characterization of complex samples like traffic emissions.
• The findings highlight the potential of parallel EI/CI TOFMS for comprehensive and sensitive analysis in environmental monitoring and other fields.