Confirmation and Quantitation of Polybrominated Biphenyls (PBBs) and Polybrominated Diphenyl Ethers (PBDEs) by MS/MS

Significance of the Topic

The widespread use and environmental persistence of polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) have led to their accumulation in water bodies and biota, posing cancer and endocrine‐related health risks. Reliable monitoring at trace levels is critical for regulatory compliance and protection of human health and ecosystems.

Objectives and Study Overview

This study evaluated the performance of a gas chromatography tandem mass spectrometry method combining an on‐column programmable temperature vaporizing (PTV) inlet with a PolarisQ ion trap MS/MS system for sensitive and selective determination of PBBs and PBDEs in natural water extracts. Key aims were to optimize injection and trap parameters, assess matrix suppression, and establish detection limits and linearity.

Methodology

Five hundred milliliter pond water samples were extracted three times with methylene chloride, dried over sodium sulfate, and concentrated under nitrogen to 5 mL in benzene. Aliquots were spiked with brominated technical mixtures for calibration and recovery studies. Standard curves spanned from picogram to nanogram levels. The on‐column PTV inlet tracked oven temperature ramps to ensure complete transfer of low‐volatility flame retardants, while MS/MS precursor and product ion transitions were selected to minimize matrix interferences.

Instrumentation Used

• PolarisQ Ion Trap MS/MS: electron ionization at 275 °C, optimized AGC and trap pressure (3 mL/min He) for maximal trapping efficiency.
• TRACE GC Ultra: Rtx™-200 column (0.25 mm×30 m, 0.25 µm), constant 2 mL/min helium flow, oven 92 °C (4 min) to 340 °C at 25 °C/min.
• On-column PTV Injector: initial 92 °C ramped to 340 °C at 0.5 °C/s.
• Autosampler: 1 µL injection with air gap and solvent plug to ensure precision.

Main Results and Discussion

The on‐column PTV inlet delivered approximately 100-fold greater analyte transfer compared to splitless injection for decabromodiphenyl ether. Optimal MS/MS trap pressure (3 mL/min) yielded five‐times higher signal than default settings. Calibration was linear over five orders of magnitude, with detection down to 350 fg on column (signal‐to‐noise 10–24). Recoveries in spiked pond water ranged from 80 % to 120 % for most congeners. MS/MS precursor→product ion selection effectively eliminated coeluting matrix interferences, enhancing specificity.

Benefits and Practical Applications

• Sub-picogram detection limits enable monitoring of trace PBBs and PBDEs in environmental samples.
• Enhanced selectivity reduces false positives from complex matrices.
• Wide dynamic range supports quantitation from low pg to tens of ng levels.
• Applicable to regulatory compliance and quality assurance in water testing laboratories.

Future Trends and Potential Applications

Advances may include coupling MS/MS traps with high‐resolution mass analyzers for broader congener coverage, integration with automated sample preparation for higher throughput, and field‐deployable GC/MS/MS platforms for on-site environmental monitoring of emerging brominated flame retardants.

Conclusion

The combination of on-column PTV injection and PolarisQ ion trap MS/MS offers a robust, sensitive, and selective approach for quantitating PBBs and PBDEs in aqueous matrices. This method overcomes volatility and matrix challenges, delivering reliable performance across a broad concentration range.

Reference

Baker D, Ragsdale JD III. Confirmation and Quantitation of Polybrominated Biphenyls and Polybrominated Diphenyl Ethers by MS/MS. Thermo Fisher Scientific Application Note 10042; 2007.