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

Significance of the Topic

Analytical assessment of polyhalogenated dioxins and furans in fire debris is crucial for understanding the exposure risks faced by firefighters and emergency responders. Elevated cancer rates among first responders at World Trade Center and other fire scenarios are linked to combustion byproducts of halogenated flame retardants. Unregulated mixed bromo‐chloro congeners may exhibit toxicity comparable to regulated chlorinated dioxins but are often overlooked in routine monitoring. Advanced analytical methods thus address critical gaps in exposure assessment and regulatory oversight.

Objectives and Study Overview

This application note demonstrates the use of atmospheric pressure gas chromatography coupled with tandem quadrupole mass spectrometry (APGC‐MS/MS) on a Waters Xevo TQ‐S platform to characterize complex mixtures of polybrominated, polychlorinated and mixed halogenated dioxins/furans (PXDD/Fs) generated in simulated household and electronics fire debris. The study aims to expand detection beyond 17 regulated chlorinated congeners to include polybrominated and mixed halogen analogues, providing semi‐quantitative concentration data for real‐world exposure matrices.

Methodology and Sample Preparation

Sample collection:

• Simulated household fire (furniture materials).
• Simulated electronics fire (office electronics).
• Post‐fire debris: ash, fragments, wipes from burn cell walls and protective gear.

Extraction and cleanup:

• Ontario Ministry of Environment Method E3418 employing 24 h Soxhlet hexane extraction with 13C‐labeled internal standards.
• Two‐stage cleanup: acid‐base silica and 5 % carbon/silica adsorbents.
• Final concentration to 100 µL before analysis.

APGC‐MS/MS conditions:

• Column: 60 m Rtx Dioxin‐2 (0.18 mm × 0.10 µm) with Sulfinert transfer line.
• Carrier gas helium, splitless injection (0.5 µL), oven gradient to 330 °C.
• Ionization: APGC positive mode via charge transfer.
• MRM methods: ~150 transitions for PXDD/Fs, ~50 for PBDD/Fs; targeting key fragments (-COBr, ‑COCl).

Applied Instrumentation

• Atmospheric Pressure Gas Chromatography (APGC).
• Xevo TQ‐S tandem quadrupole MS.
• MassLynx MS software.

Main Results and Discussion

Wide congener coverage: Mono‐ to hepta‐halogenated dioxins/furans identified across both fire types. Electronics fire debris, particularly contaminated helmet wipes, exhibited the highest concentrations and diversity of polybrominated dibenzofurans (PXDFs).

Semi‐quantification:

• Concentrations spanned parts‐per‐trillion to parts‐per‐billion (ng/g) per congener group.
• Household fire samples: PXDF levels ranged from 0.01–82 ng/g for various Br/Cl patterns.
• Electronics fire samples: PXDF levels reached up to 9,254 ng/g for Br4DF and >6,000 ng/g for Br3DF isomers.

Isomer complexity: Numerous unresolved isomer peaks per substitution pattern observed, demonstrating intricate formation pathways during combustion. Signal‐to‐noise figures of 12–89 confirm instrument sensitivity.

PXDDs also detected at lower concentrations and with fewer congeners, underlining the predominance of furans in particulate deposition.

Benefits and Practical Applications

Implementation of APGC‐MS/MS with Xevo TQ‐S offers:

• Enhanced sensitivity and selectivity for trace PXDD/F analysis in complex matrices.
• Capability to monitor previously unregulated congeners, improving risk assessment for first responders.
• Comprehensive MRM database enabling routine surveillance of mixed halogen congeners.

Future Trends and Potential Applications

• Expansion of commercial standards for PBDD/F and PXDD/F congeners to refine quantification.
• Integration of high‐resolution time‐of‐flight APGC platforms for non‐targeted screening.
• Development of field‐deployable soft‐ionization instruments for on‐scene monitoring.
• Regulatory adaptation to include mixed halogen dioxins and furans in routine environmental and occupational surveillance.

Conclusion

The APGC‐MS/MS method on Waters Xevo TQ‐S successfully characterizes a broad array of polyhalogenated dioxins and furans in fire debris matrices, revealing significant occurrences of unregulated congeners. This approach enhances exposure assessment for emergency responders and supports regulatory advancement by illuminating complex dioxin/furan profiles beyond current monitoring scopes.

Reference

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3. Eljarrat E, Feo ML, Barcelo D. In Handbook of Environmental Chemistry: Brominated Flame Retardants; Springer, 2011:187–202.
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5. Ontario Ministry of Environment Method DFPCB‐E3418. Toronto, ON, 2010.