Analysis of Halogenated Polycyclic Aromatic Hydrocarbons in Atmosphere around Metallurgical Plants by 7250 High-resolution GC/Q-TOF

Importance of the Topic

Halogenated polycyclic aromatic hydrocarbons and polychlorinated naphthalenes are persistent organic pollutants with significant toxicological impacts. Metallurgical operations are known sources of these compounds in the atmosphere. Accurate measurement at trace levels is essential for environmental monitoring and risk assessment.

Study Objectives and Overview

This study evaluates the performance of a high-resolution GC/Q-TOF system operating in full-spectrum mode for simultaneous target quantitation and non-target screening of halogenated PAHs and PCNs in air samples collected around an iron ore sintering plant.

Methodology

Air samples were collected by high-volume samplers following US EPA method TO-9A. The gas phase was captured on polyurethane foam, extracted by accelerated solvent extraction, and cleaned with silica and carbon columns. Target analytes included 13 chlorinated and 17 brominated PAH congeners and eight PCN congeners quantified by isotopic dilution. Priority non-halogenated PAHs were also quantified. Data processing employed MassHunter software for qualitative, quantitative, and unknown analysis with SureMass deconvolution and NIST library matching.

Used Instrumentation

Analysis was performed on an Agilent 7250 GC/Q-TOF system equipped with a novel ion source and a DB-5ms UI capillary column (60 m × 0.25 mm × 0.25 μm). Splitless injection at 60 °C inlet ramped to 300 °C, helium carrier gas at 1 mL/min, oven programming from 55 °C to 305 °C, source temperature 250 °C, quadrupole 150 °C, mass range m/z 50–600, and acquisition rate 5 Hz.

Key Results and Discussion

Calibration curves for halogenated PAHs were linear from 5 to 500 pg/μL with R2 > 0.99 and RSDs < 10 %. Accurate mass extraction (±15 ppm) effectively reduced matrix interference. Target PAH concentrations in ambient air ranged from 0.12 to 101.2 pg/m3. PCN congeners were detected between 0.01 and 0.23 pg/m3. Full-spectrum data enabled identification of additional halogenated and non-halogenated PAHs through retrospective analysis.

Benefits and Practical Applications

• Simultaneous target quantitation and non-target screening without additional runs
• High sensitivity and selectivity for trace-level pollutants
• Retrospective data mining and extended analytical scope
• Improved efficiency with advanced deconvolution and library matching tools

Future Trends and Potential Applications

Emerging applications include real-time environmental surveillance, integration with high-throughput data analytics, expansion to other classes of persistent pollutants, and support for regulatory compliance and source apportionment studies.

Conclusion

The Agilent 7250 GC/Q-TOF system operating in full-spectrum mode provides a powerful platform for comprehensive analysis of halogenated PAHs and PCNs in complex atmospheric samples, combining robust quantitation with flexible non-target investigation.

References

1. Lili Yang, Guorui Liu, Minghui Zheng et al Sci Total Environ, 2017, 580, 1146-1154
2. Rong Jin, Guorui Liu, Minghui Zheng et al J Chromatogr A, 2017, 1509, 114-122