Overcoming analytical challenges for polybrominated diphenyl ethers (PBDEs) analysis in environmental samples using gas chromatography – Orbitrap mass spectrometry

Importance of the Topic

Polybrominated diphenyl ethers (PBDEs) are widely applied flame retardants that persist in the environment and bioaccumulate in food chains. Their resistance to degradation, potential for long-range transport, and links to endocrine disruption and cancer have led to regulatory bans on penta-, tetra-, and deca-BDE formulations. Accurate, selective, and sensitive analysis of PBDEs at trace levels in complex environmental matrices remains a practical challenge for laboratories involved in monitoring and compliance.

Objectives and Study Overview

This study aimed to evaluate the quantitative performance of the Thermo Scientific™ Exactive™ GC Orbitrap™ GC-MS system coupled with a TRACE™ 1310 gas chromatograph for targeted analysis of 27 PBDE congeners in environmental samples. Key goals included assessing chromatographic resolution, instrument sensitivity, mass accuracy, linearity, repeatability, and method robustness across sediment, sludge, filter dust, and air matrices.

Methodology

Environmental samples (sediment, sludge, filter dust, and air) were Soxhlet-extracted with toluene for 24 h, followed by alumina cleanup using n-hexane/DCM elution. Extracts were concentrated, spiked with 13C-labelled PBDE surrogate and recovery standards, and analyzed by GC-Orbitrap MS.

Instrumentation

• Gas chromatograph: Thermo Scientific TRACE 1310 with PTV large-volume injection and TraceGOLD TG-PBDE column (15 m × 0.25 mm I.D., 0.10 µm film).
• Autosampler: TriPlus RSH with Instant Connect PTV liner.
• Mass spectrometer: Exactive GC Orbitrap MS, operated in EI full-scan at 60 000 FWHM, mass range 68–1000 Da, mass accuracy <0.5 ppm after rapid FC-43 calibration.
• Data system: Chromeleon CDS 7.2 for acquisition, processing, and reporting with targeted-SIM methods.

Key Results and Discussion

• Chromatography: Complete separation of 27 PBDEs in under 11 min, including critical pairs (e.g., BDE-49/BDE-71).
• Sensitivity and Detection Limits: All congeners detected at the lowest calibration levels (1 ng/mL mono- to penta-, 2 ng/mL hexa- to octa-, 5 ng/mL nona- to deca-BDE); instrument detection limits between 6 and 260 fg on column (99% confidence).
• Mass Accuracy and Selectivity: Consistent <2 ppm mass errors across isotopic clusters enabled clear identification in complex matrices.
• Linearity and Precision: Five-point calibration showed R² > 0.995 and residual %RSD < 13%; matrix repeatability (n = 12) yielded quantifier/qualifier peak-area %RSD of 2–10%.
• Sample Analysis: Predominant congeners included BDE-209, 207, 206, and 99 in sludge; BDE-209, 47, 99 in dust; BDE-99, 47, 100 in air; BDE-15, 47, 99 in sediment.

Benefits and Practical Applications

• Rapid, high-throughput quantification of PBDEs with robust reproducibility.
• Enhanced selectivity in challenging matrices due to high resolution and mass accuracy.
• Isotopic dilution workflow ensures accurate recovery correction and quantitation.
• Comprehensive data handling and reporting through Chromeleon CDS.

Future Trends and Applications

Advances may include integration of Orbitrap GC-MS for nontarget screening of emerging brominated contaminants, further automation of sample preparation, and expanded regulatory monitoring. Continued improvements in resolution and data analytics will support broader environmental and food safety applications.

Conclusion

The Thermo Scientific Exactive GC Orbitrap GC-MS method provides a fast, sensitive, and selective solution for routine analysis of 27 PBDE congeners in diverse environmental samples. It meets critical requirements for chromatographic separation, mass accuracy, linearity, and precision, enabling reliable monitoring of persistent organic pollutants.

References

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2. Hites R.A. Polybrominated diphenyl ethers in the environment and in people: A meta-analysis of concentrations. Environ. Sci. Technol. 2004;38:945–956.
3. Costa L.G., Giordano G., Tagliaferri S., Caglieri A., Mutti A. Polybrominated diphenyl ether (PBDE) flame retardants: Environmental contamination, human body burden and potential adverse health effects. Acta Biomed. 2008;79(3):172–183.
4. UNEP Stockholm Convention. Guidance for the inventory of polybrominated diphenyl ethers (PBDEs) listed under the Stockholm Convention on POPs. Accessed May 8, 2018.