Routine, regulatory analysis of dioxins and dioxin-like compounds in food and feed samples

Significance of Topic

Monitoring dioxins and dioxin-like compounds in food and feed is critical to public health and regulatory compliance. These persistent organic pollutants (POPs) bioaccumulate in animal fatty tissues and enter the human food chain, posing carcinogenic and endocrine-disrupting risks. The shift in EU legislation allowing triple quadrupole GC-MS/MS as a confirmatory technique created demand for robust, high-throughput methods to replace traditional high-resolution mass spectrometry.

Objectives and Study Overview

The study aimed to validate the Thermo Scientific™ TSQ™ 9000 AEI GC-MS/MS system, coupled with TRACE 1310 GC and Chromeleon CDS software, for routine, regulatory-compliant quantification of PCDD/Fs, dioxin-like PCBs and indicator PCBs in food and feed. Two geographic sites (UK and USA) and multiple operators performed parallel analyses on hundreds of samples, including proficiency test materials and certified reference materials, to demonstrate sensitivity, accuracy, precision, linearity, and robustness.

Methodology and Instrumentation

The analytical workflow used Thermo’s TRACE 1310 GC with a multiphase TG-Dioxin capillary column, TriPlus RSH autosampler, and TSQ 9000 with Advanced Electron Ionization (AEI). Samples (≤2 g fat or wet weight) underwent hot or pressurized extraction, automated three-column cleanup (acidic silica, alumina, carbon), and fractionation of non-ortho PCBs/PCDD/Fs and mono-/di-ortho plus indicator PCBs. Calibration employed isotopically labelled 13C standards at eight levels for PCDD/Fs and seven for PCBs. Chromeleon CDS performed acquisition, isotopic-dilution calculations, peak integration, IR and RF evaluations, and compliance reporting.

Main Results and Discussion

• Chromatography: The 60 m TG-Dioxin column separated 17 toxic PCDD/Fs and 18 PCBs in <45 min, eliminating co-elution issues (e.g. PeCDF congeners).
• Sensitivity and LOQs: Calibration-based LOQs achieved 0.15 pg/g WHO-PCDD/F-TEQ for a 2 g fat sample, meeting 1/5th ML requirements except for infant food and terrestrial animal liver.
• Linearity and Precision: RF %RSDs <6% across four orders of magnitude and coefficient of determination (R2) ≥0.994 for all congeners.
• Accuracy: Results for 29 samples and certified material WMF-01 agreed within ±6% of EU Reference Laboratory (EURL) values. Pearson correlations were ≥0.99 for PCDD/Fs, dioxin-like PCBs, and indicators.
• Robustness: A two-week sequence with 161 injections (40 matrix extracts, 40 LOQ checks) without maintenance demonstrated signal repeatability (RSD <7%) and stable IRs under heavy matrix load.

Benefits and Practical Applications

The validated method delivers regulatory-grade data with high throughput, reduced maintenance downtime, and fully integrated data processing on one software platform. Automating isotope-dilution calculations and conforming to EU method EN 1948 streamlines quality control, minimizes transcription errors, and supports routine surveillance of food/feed safety.

Future Trends and Potential Applications

Advances may include further miniaturization of extraction/cleanup, enhanced multiplexing of analyte classes (e.g. PFAS alongside dioxins), and real-time data quality dashboards. Integration with laboratory information management systems (LIMS) and machine-learning tools could optimize sequence planning, predictive maintenance, and automated compliance reporting to meet evolving regulatory demands worldwide.

Conclusion

The TSQ 9000 AEI GC-MS/MS system with Chromeleon CDS offers robust, precise, and accurate analysis of dioxins and dioxin-like compounds in complex food and feed matrices. It fulfills EU regulatory criteria for sensitivity, selectivity, and throughput, providing a cost-effective alternative to high-resolution MS without sacrificing performance.

Reference

1. WHO. Dioxins and their effects on human health. WHO Fact Sheet. 2019.
2. EC Commission Regulation (EU) 2017/644. Off. J. Eur. Union. L 92:9–34.
3. EC Commission Regulation (EU) 2017/771. Off. J. Eur. Union. L 115:22–42.
4. Thermo Fisher Scientific. Low level quantification of PCDD/Fs in animal feed using TSQ 9000 AEI GC-MS/MS. Application Note AN10590.
5. EU JRC. Guidance on estimation of LOD and LOQ for contaminants in feed and food.
6. EC Directive 2002/32/EC on undesirable substances in animal feed.
7. US EPA Method 1613, Revision B (1994).
8. EC Commission Regulation (EC) No 1881/2006 setting MLs for certain contaminants in foodstuffs.