Analysis of Combustion Byproducts on Firefighter Protection Equipment Using a Novel High-Resolution GC/Q-TOF

Significance of the Topic

Firefighters are routinely exposed to complex mixtures of toxic combustion byproducts during fire incidents. Among these, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and other halogenated compounds pose significant health risks due to their carcinogenic and mutagenic properties. High-resolution mass spectrometry in untargeted full-spectrum mode enables comprehensive detection and identification of trace contaminants on protective equipment, informing exposure assessment and risk mitigation.

Objectives and Study Overview

This application brief details the use of a novel high-resolution Agilent 7250 GC/Q-TOF system to characterize and semiquantify PAHs, PBDEs, and other combustion byproducts on firefighters’ helmets and neck hoods before and after controlled burns. The goal was to (1) establish an untargeted screening workflow, (2) confirm compound identities via spectral libraries and retention indices, and (3) assess relative contaminant levels across sample types.

Methodology and Used Instrumentation

Sample Collection and Extraction

• Wipe sampling of 4 in² areas on helmet and neck hood pre- and post-fire using cotton cloth moistened with isopropanol.
• Dual extraction of wipes with 10 mL dichloromethane, combined extracts evaporated to 1 mL.

Instrumental Analysis

• Gas chromatograph: Agilent 7890B GC.
• Mass spectrometer: Agilent 7250 GC/Q-TOF, resolving power 25 000 at m/z 272.
• Column: DB-5MS (30 m × 0.25 mm, 0.25 µm); helium carrier gas at 1.5 mL/min constant flow.
• Oven program: 50 °C for 3 min, ramp 10 °C/min to 300 °C, 7 min hold.
• Injection: 1 µL splitless at 280 °C.
• Electron ionization: standard 70 eV and low-energy modes at 15 eV and 12 eV.
• Mass range: m/z 50–1200; acquisition rate: 5 Hz; source at 240 °C (70 eV) or 200 °C (≤15 eV); quadrupole at 150 °C.

Data Processing

• Feature detection with SureMass algorithm and Unknowns Analysis B.08.00.
• Compound identification via NIST14 EI spectral library matching and retention index confirmation.
• Formula validation using isotope cluster evaluation and Molecular Formula Generator in MassHunter Qualitative Analysis.
• Semiquantification of PAHs using MassHunter Quantitative Analysis B.08.00.

Main Results and Discussion

• PAH Detection: Post-fire wipes revealed over 50 distinct PAH species on helmets, including regulated compounds such as naphthalene, phenanthrene, and benzo[a]pyrene, all confirmed by library match and RI alignment.
• Abundance Trends: Fluoranthene and pyrene were the most abundant PAHs; total PAH levels were higher on helmets than on neck hoods.
• Brominated Compounds: Tri-, tetra-, penta-, and hexa-BDE isomers, along with novel brominated byproducts (e.g., C6H4Br2O, C16H9Br), were detected exclusively post-fire, indicating deposition from smoke.
• Role of Low-Energy EI: Reduced electron energies improved preservation of molecular ions for unknown brominated species, enhancing formula assignment through accurate isotope patterns.
• Protective Gear Performance: Detection of contaminants on neck hoods post-fire suggests incomplete protection by standard turnout gear.

Benefits and Practical Applications

The high-resolution GC/Q-TOF workflow delivers sensitive, untargeted screening of diverse combustion byproducts on protective equipment. It supports exposure biomarker discovery and quantitative assessment, aiding occupational health monitoring, decontamination protocol optimization, and regulatory compliance in fire service settings.

Future Trends and Opportunities

• Development of portable or field-deployable high-resolution MS systems for on-site contaminant monitoring.
• Extension of untargeted workflows to additional matrices such as turnout gear textiles, air samples, and biological fluids.
• Application of machine learning and advanced data analytics for automated pattern recognition and novel contaminant identification.
• Standardization of sampling and analysis protocols to enable longitudinal studies and cross-department comparisons.

Conclusion

The demonstrated Agilent 7250 GC/Q-TOF method effectively identifies and semiquantifies a wide range of PAHs, PBDEs, and other combustion byproducts on firefighter equipment. Its high sensitivity, selectivity, and untargeted acquisition capabilities make it a valuable tool for comprehensive exposure assessment and occupational health research in fire service operations.

References

1. Bates MN. Registry-based case-control study of cancer in California firefighters. Am J Ind Med. 2007;50(5):339–344.
2. Kang D et al. Cancer incidence among male Massachusetts firefighters 1987–2003. Am J Ind Med. 2008;51(5):329–335.
3. Fernando S et al. Evaluation of firefighter exposure to wood smoke during training exercises at burn houses. Environ Sci Technol. 2016;50:1536–1543.