APGC-MS/MS Investigation of a Complex Mixture of Polyhalogenated Dioxins and Furans (PXDD/Fs) Generated in Fire Debris

Importance of the Topic

The combustion of modern materials releases a complex mixture of halogenated dioxins and furans, some of which remain unregulated. Firefighters and first responders face elevated cancer risks linked to exposure at fire scenes, but routine monitoring focuses only on chlorinated congeners. Expanding analytical capabilities to include polybrominated (PBDD/Fs) and mixed bromo-chloro species (PXDD/Fs) is critical for accurate exposure assessment and risk management.

Study Objectives and Overview

This study aimed to develop and apply a sensitive and selective atmospheric pressure gas chromatography–tandem quadrupole mass spectrometry (APGC-MS/MS) method for the characterization of polyhalogenated dioxins and furans generated during simulated household and electronics fires. By quantifying mono- through hepta-substituted congeners, the work seeks to reveal the true burden of toxic by-products to which first responders are exposed.

Methodology and Instrumentation

Samples were produced at a dedicated training facility, simulating a household furniture fire and an electronics fire. Debris, ash and wipe samples from burn cells and firefighter equipment were collected post-extinguishment. Extraction followed the Ontario MOECC E3418 protocol: Soxhlet extraction in hexane (24 h) with fortification by 13C-labeled internal standards covering key PCDD/F and PCDF congeners. Cleanup utilized sequential acid-base silica and 5% carbon/silica columns. Final extracts were concentrated to 100 µL.

Instrumentation

• Gas chromatograph: 60 m Rtx Dioxin-2 capillary column with helium carrier.
• Ionization source: APGC positive mode, charge transfer mechanism.
• Mass spectrometer: Waters Xevo TQ-S triple quadrupole.
• MRM transitions: ~150 for PXDD/PXDF and ~50 for PBDD/PBDF groups, monitoring key fragment ions (–COBr, –COCl).
• Oven program: multi-step temperature gradient from 120 °C to 330 °C.

Main Results and Discussion

The method enabled detection of over 40 PXDD/F congener groups, from mono- to heptabromo/chloro substituted species, at trace levels (ppt to ppb). Electronics-fire debris exhibited the highest diversity and concentrations, reflecting abundant brominated flame retardants in e-waste. Firefighter helmet wipes yielded the highest particulate-associated levels of polyhalogenated furans, underscoring direct occupational exposure. The extensive isomeric complexity was evidenced by multiple unresolved peaks per substitution pattern, with signal-to-noise ratios from 12 to 89. Semi-quantitative results, based on 13C standards, highlighted concentration ranges from 0.01 to over 9,000 ng/g across different PXDF groups.

Contributions and Practical Applications

By extending routine dioxin/furan analysis beyond chlorinated congeners, this APGC-MS/MS approach improves understanding of firefighter exposure to unmonitored toxicants. The sensitivity and selectivity of the Xevo TQ-S facilitate broad screening in complex matrices, supporting more comprehensive risk assessments, enhanced personal protective equipment evaluation, and potential refinement of regulatory guidelines.

Future Trends and Applications

As interest grows in mixed-halogen pollutants, future work may focus on:

• Expanding congener libraries and reference standards for full quantification.
• Adopting high-resolution time-of-flight MS for non-targeted screening.
• Integrating real-time sampling or portable APGC devices for on-scene monitoring.
• Performing toxicological studies to establish toxicity equivalency factors for PBDD/Fs and PXDD/Fs.

Conclusion

The combination of APGC and tandem quadrupole MS on the Xevo TQ-S platform delivers a robust solution for profiling complex polyhalogenated dioxins and furans in fire debris. These findings underscore the urgent need to include brominated and mixed halogen congeners in exposure monitoring protocols, ultimately enhancing occupational health protection.

References

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• Weber R, Kuch B. Formation of brominated and mixed halogenated dibenzo-p-dioxins and dibenzofurans during combustion processes. Environ Int 2003;29:699–710.
• Ontario Ministry of Environment. Method DFPCB-E3418: Dioxin/Furan Analysis. Toronto, ON;2010.