Analysis of Dioxins in Feed and Food Using GC-MS/MS as Confirmatory Method in Complying with EU Regulation

Significance of the Topic

The reliable detection and quantification of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), collectively known as dioxins, is critical due to their persistence, bioaccumulation in fats, and potential carcinogenicity. Regulatory bodies, including the European Union, require stringent confirmatory methods to monitor these contaminants in feed and food, ensuring public health protection and compliance with international conventions such as the Stockholm Convention.

Objectives and Study Overview

This study evaluates the performance of Shimadzu’s GCMS-TQ8040 triple quadrupole GC-MS/MS system as a confirmatory method under EU Regulation No. 589/2014. The goal is to identify and quantify the 17 most toxic dioxin congeners in mixed standards, compound feed, and animal-derived food samples, and to demonstrate compliance with regulatory sensitivity, selectivity, and repeatability criteria.

Methodology and Instrumentation

A Shimadzu GCMS-TQ8040 was coupled with an AOC-20i+s auto-injector and an Rxi-5Sil MS capillary column. Samples (eggs, animal fats, compound feeds) were spiked with 13C-labelled internal standards, extracted via Power-Prep, cleaned using DEXTech, concentrated to 20 µL, and analyzed in splitless mode. Key MS parameters included unit mass resolution (0.9 amu), MRM acquisition with two transitions per congener, and collision energies optimized per analyte. Calibration employed isotope-dilution with seven concentration levels tailored to congener toxicity.

Key Results and Discussion

Retention and resolution requirements were met, with critical isomer pairs showing less than 0.3% peak overlap and Rs >1.4. Calibration curves displayed excellent linearity (R² >0.998) over ranges from 0.5–200 ng/mL for tetra-CDD/F up to 5–2000 ng/mL for octa-CDD/F. Limits of quantitation corresponded to the lowest calibration levels (0.5–5 pg/µL), and limits of detection were estimated at 0.1–1.6 pg/µL, within the femtogram range mandated by the EU. Repeatability at LOQ levels yielded %RSD <10% for all congeners. Application to real samples provided total toxic equivalent (TEQ) values by multiplying measured concentrations with WHO TEFs; one positive sample exhibited 48.8 ng TEQ/kg, exceeding allowable limits of 0.75–1.5 ng TEQ/kg.

Benefits and Practical Applications

• High-throughput, cost-effective confirmatory analysis for routine QC in food safety laboratories.
• Robust compliance with EU criteria for sensitivity, selectivity, and repeatability.
• Comprehensive coverage of all regulated congeners with isotope-dilution quantitation.

Future Trends and Potential Applications

Advances may include higher multiplexing with fast-scanning MS/MS, integration of automated sample preparation, and expansion to other persistent organic pollutants. Emerging applications could target rapid screening workflows and on-site monitoring using portable GC-MS systems.

Conclusion

Shimadzu’s GCMS-TQ8040 coupled with optimized MRM methodology meets or exceeds EU confirmatory requirements for dioxin analysis in feed and food. The approach delivers high sensitivity, selectivity, and precision, ensuring reliable TEQ determination and regulatory compliance.

References

1. EU Regulation 152/2009.
2. Toxicological Sciences 93(2), 223–241 (2006).
3. EU Regulation 589/2014.
4. EU Regulation 277/2012.