Meeting the challenges of Dioxin analysis and more with GC-Orbitrap high mass resolution capabilities

Importance of the Topic

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) are persistent environmental pollutants with high toxicity, regulated worldwide at sub-picogram levels. Analytical methods must deliver extreme sensitivity, selectivity, and accuracy to ensure compliance with stringent limits in soil, food, and environmental matrices.

Aim and Overview

This study evaluates the performance of a Thermo Scientific Orbitrap Exploris GC mass spectrometer coupled to a capillary GC system for trace quantification of PCDD/Fs in soil according to EPA Method 1613. The goal is to demonstrate femtogram-level sensitivity, high mass resolution, and reliable quantitation using a streamlined isotopic dilution workflow in Chromeleon CDS.

Methodology and Instrumentation

A two-gram soil sample was extracted with an acetonitrile/hexane biphasic mixture, centrifuged, and concentrated before spiking with isotopically labeled standards. Chromatographic separation employed a 60 m TG-Dioxin capillary column on a Thermo Scientific TRACE 1610 GC. Mass analysis used the Orbitrap Exploris GC 240 at 60 000 resolution (FWHM at m/z 200), providing > 40 000 resolving power at higher masses. Data acquisition and quantification were managed in Chromeleon CDS 7.3.2 with a dedicated Dioxin Analyzer workflow.

Main Results and Discussion

The system achieved a linear calibration range from 0.05 to 100 pg/µL and demonstrated femtogram-level limits of detection for 2,3,7,8-TCDD. Measured mass resolving power exceeded EPA 1613 criteria (> 10 000 at 5 % valley) even for high-mass congeners such as OCDD (m/z 455). Ion ratio deviations and relative response factors met regulatory tolerances. Results from spiked soil extracts correlated closely with those obtained on a TSQ 9610 GC-MS/MS system, confirming accuracy and precision at fg levels.

Benefits and Practical Applications

• Femtogram sensitivity and high mass accuracy facilitate compliance with global regulations.
• Full-scan high-resolution data enable retrospective screening for unknown contaminants.
• Integrated software workflow reduces manual data handling and ensures audit-ready reporting.
• Single-instrument flexibility supports method expansion beyond PCDD/Fs.

Future Trends and Opportunities

Advancements in ultrahigh-resolution mass spectrometry will further improve detection of emerging dioxin-like compounds. Automation in sample preparation and data processing will enhance throughput. Integration of comprehensive databases with high-resolution workflows may enable rapid identification of novel environmental pollutants.

Conclusion

The GC-Orbitrap high-resolution mass spectrometry approach provides a robust, sensitive, and compliant solution for trace dioxin analysis in environmental samples. Its combination of femtogram sensitivity, high resolving power, and streamlined data processing makes it a valuable alternative for laboratories facing evolving analytical challenges.

References

1. U.S. EPA. Method 1613: Tetra- through Octa-Chlorinated Dioxins and Furans by Isotope Dilution GC/HRMS.
2. Wellington Laboratories. Isotopically Labeled PCDD/F Calibration Standards.
3. Thermo Fisher Scientific. TSQ 9610 GC-MS/MS System Performance Evaluation.