Fast, ultra-sensitive analysis of PBDEs in food using advanced GC-MS/MS technology

Importance of the Topic

The analysis of polybrominated diphenyl ethers (PBDEs) in food is critical for food safety and public health monitoring because these persistent organic pollutants bioaccumulate and pose carcinogenic risks. Advanced analytical methods able to detect ultra-trace levels of multiple PBDE congeners simultaneously are essential to comply with regulatory limits and support international conventions such as the Stockholm Convention.

Objectives and Study Overview

This study evaluated the quantitative performance of the Thermo Scientific™ TSQ™ 9000 triple quadrupole GC-MS/MS system equipped with an advanced electron ionization (AEI) source for rapid, sensitive, and selective determination of 27 PBDE congeners in food. Key performance criteria included sensitivity (instrument detection limits and quantification limits), linearity, repeatability, accuracy against GC-HRMS data, and sample throughput.

Methodology and Instrumentation Used

The method employed trace-level isotope dilution with 16 13C-labeled internal standards and fast GC separation on a Thermo Scientific™ TraceGOLD™ TG-PBDE 15 m × 0.25 mm × 0.10 μm capillary column. Sample preparation involved homogenization/freeze-drying, fortified silica/charcoal cleanup, solvent evaporation, and final reconstitution in n-nonane. Analysis was performed on a TSQ 9000 GC-MS/MS coupled to a TRACE 1310 GC with PTV injection. Timed-SRM acquisition provided high selectivity, while the AEI source and optimized transfer line heating improved ionization efficiency, particularly for high-brominated congeners.

Key Results and Discussion

• Chromatographic Separation and Throughput: All 27 native PBDE congeners were baseline separated in under 11 minutes, including critical isobaric pairs BDE-49/BDE-71 (0.6% valley resolution), enabling up to 100 samples per day (3× faster than 45 min GC-HRMS methods).
• Sensitivity: Instrument detection limits (IDLs) ranged from 2 to 100 fg on-column (0.003–0.125 ng/kg in fat). Limits of quantification (LOQs) were 0.05–0.63 ng/kg in sample matrix, meeting acceptance criteria of <15% RSD peak area and ion ratios within ±30% of calibration values.
• Linearity and Repeatability: Calibration across 1–2000 pg/μL (mono-penta), 2–800 pg/μL (hexa-octa) and 5–2000 pg/μL (nona-deca) yielded R² > 0.98 and RRF RSD < 10% for all congeners.
• Selectivity in Complex Matrices: Timed-SRM efficiently suppressed background interferences such as acylglycerides in fish oil, delivering clean PBDE quantification even in heavily fortified samples.
• Accuracy against GC-HRMS: Comparative analysis of real food extracts (salmon, tallow, fish oil, liver, reindeer, milk) showed agreement within ±25% of GC-HRMS results, with confirmation ion ratios within ±30% tolerance.

Benefits and Practical Applications

• Rapid, high-throughput screening of PBDEs at ppt levels in diverse food matrices.
• Reliable quantification and confirmation in compliance with EPA and Stockholm Convention requirements.
• Reduced cost per analysis due to shorter run times and efficient column performance.
• Integrated data processing with Chromeleon™ CDS for streamlined method development, control, and reporting.

Future Trends and Potential Applications

Expanding multiplexed GC-MS/MS methods to cover a broader range of persistent organic pollutants and degradants, integrating automated sample preparation workflows, and further enhancing ionization sources for next-generation MS detectors. Coupling with ambient ionization techniques and high-resolution MS may open new avenues for rapid on-site screening and comprehensive environmental monitoring.

Conclusion

The TSQ 9000 GC-MS/MS system with AEI source delivers unparalleled sensitivity, selectivity, and throughput for PBDE analysis in food. It matches or exceeds GC-HRMS performance at ultra-trace levels, providing a robust, cost-effective solution for routine food safety laboratories.

Reference

• Hites RA. Polybrominated Diphenyl Ethers in the Environment and in People: A Meta-Analysis of Concentrations. Environ Sci Technol. 2004;38:945–956.
• Stockholm Convention. Guidance for the inventory of PBDEs listed under the Stockholm Convention on POPs. 2018.
• Fernandes A, White S, D’Silva K, Rose M. Simultaneous determination of PCDDs, PCDFs, PCBs and PBDEs in food. Talanta. 2004;63:1147–1155.
• Thermo Fisher Scientific. Timed SRM technical note. 2009.
• US EPA Method 1614A. Brominated Diphenyl Ethers in Water, Soil, Sediment, and Tissue by HRGC/HRMS. 2010.