Advancements in Increasing Resolution in Multi Reflecting TOF Mass Spectrometry with Folded Flight Path

Significance of the Topic

High resolution in mass spectrometry offers critical improvements in detecting trace analytes in complex matrices such as environmental, biological, and petrochemical samples. Recent innovations in multi-reflecting time-of-flight (TOF) analyzers extend the performance envelope for gas chromatography–high resolution mass spectrometry (GC–HRMS), enabling enhanced sensitivity, resolving power, and throughput for modern analytical workflows.

Objectives and Study Overview

This study presents the development and experimental validation of a prototype folded flight path (FFP) mass analyzer integrated with an electron impact (EI) source for GC–HRMS. The primary goals include achieving higher order spatial and energy focusing to surpass 100,000 resolving power (FWHM), improving duty cycle via advanced multiplexing, and demonstrating the system performance on complex sample matrices.

Methodology and Used Instrumentation

The novel FFP analyzer design incorporates 4th order energy focusing and full 3rd order spatial focusing combined with custom-optimized ion mirror geometries. Simulation tools (Axion, SIMION, Ion Tracer) guided electrode geometry and voltage configurations. A multiplexing method, Encoded Frequent Pulsing™ (EFP™), enhances duty cycle by 10–100×, supporting high acquisition rates up to 200 spectra per second. The assembled prototype couples the FFP analyzer to an EI ion source within a GC–HRMS setup.

Main Results and Discussion

Experimental evaluation using urine spiked at 0.5 ng/µL and petroleum samples demonstrated resolving power exceeding 100,000 across m/z 10–1500. A challenging C3/SH4 doublet (Δ3.37 mDa) in a crude oil matrix was baseline resolved at a prototype resolving power of 150,000. Analysis of methaqualone and strychnine peaks confirmed mass accuracy within ±1 ppm, with clear separation in GC chromatograms at low concentration levels.

Benefits and Practical Applications

• Unambiguous identification of low‐level analytes in complex matrices.
• Compatibility with fast chromatographic separations (GC, GC×GC).
• High throughput via fast acquisition and improved duty cycle.
• Expanded dynamic range and lower detection limits.

Future Trends and Potential Applications

Continued integration of high‐order focusing optics with advanced multiplexing is expected to push resolving power beyond 200,000 while maintaining sub‐ppm mass accuracy. Future applications include comprehensive petroleomics, real‐time metabolomics, and environmental monitoring, as well as coupling with additional ionization sources and separation techniques for multidimensional analysis.

Conclusion

The prototype multi‐reflecting TOF analyzer with folded flight path and EFP multiplexing delivers unprecedented combination of ultra‐high resolution, high duty cycle, and rapid data acquisition. This technology broadens analytical capabilities for trace analysis in diverse scientific and industrial fields.

References

1. LECO Corporation. Folded Flight Path® TOF Mass Analyzer. LECO White Paper.
2. Willis P, et al. High Resolution Multi-Reflecting TOFMS with Multiplexing by Encoded Frequent Pulsing for Increasing the Duty Cycle. ASMS 2015 Proceedings.