An Inter-Laboratory Evaluation of a Confirmatory Method For Dioxins in Food and Environmental Samples Using APGC-MS/MS

Significance of the Topic

Persistent organic pollutants such as polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulate in the environment and food chain, posing serious health risks. Regulatory agencies worldwide mandate precise, confirmatory analytical methods at very low detection levels. The recent authorization of tandem mass spectrometry (GC-MS/MS) under EU Regulation 589/2014 has created an opportunity to employ more accessible benchtop systems in place of high-resolution magnetic sector instruments.

Objectives and Study Overview

This inter-laboratory study evaluated the performance and robustness of Atmospheric Pressure Gas Chromatography (APGC) coupled to Xevo TQ-S triple quadrupole MS for confirmatory dioxin analysis in food and environmental matrices. Four laboratories in Sweden, Spain, Germany, and the UK compared APGC-MS/MS results with established GC-EI-HRMS data using certified reference and proficiency testing materials.

Methodology and Instrumentation

The method employed a DB-5MS or BPX-5 capillary column with pulsed splitless or programmed temperature vaporisation injection, helium carrier gas, and nitrogen auxiliary gases. MS acquisition used MRM transitions optimized for molecular ion [M+•] fragmentation (loss of CO+35Cl) under collision energies of 30–40 eV. Calibration standards (EPA-1613 series) and 13C-labelled internal standards ensured quantitation down to tens of femtograms on-column. Sample preparation followed validated EU and EPA protocols for milk powder, sludge, fly ash, animal fats, fish oil, eggs, and blood.

Key Results and Discussion

The APGC-TQ-S achieved signal-to-noise ratios >50 at 10 fg/µL, and detection of TCDD congeners at 2 fg on-column. Linearity (R2>0.998), repeatability (RSD<15 %), and ion ratio selectivity met or exceeded HRMS criteria. Inter-laboratory comparisons showed agreement within ±7 % relative difference versus GC-HRMS across diverse matrices. QA/QC requirements for separation, response factors, and ion abundance ratios complied fully with EPA-1613 and EN 16215 standards.

Benefits and Practical Applications

• High sensitivity and specificity comparable to high-resolution instruments
• Robust, reproducible performance across multiple sites
• Easier maintenance and lower operational complexity of benchtop equipment
• Full compliance with EU and EPA confirmatory criteria for PCDD/F analysis

Future Trends and Opportunities

The demonstrated APGC-MS/MS approach paves the way for broader implementation in routine food and environmental monitoring laboratories. Ongoing developments may include automated sample introduction, expanded target lists for dioxin-like compounds, and integration with high-throughput data processing workflows. Further collaborative studies could extend to sediment, soil, and human biomonitoring.

Conclusion

This inter-laboratory evaluation confirms that APGC coupled to a triple quadrupole MS provides a validated, regulatory-compliant confirmatory method for dioxins in complex matrices. It matches the analytical performance of GC-EI-HRMS while offering greater ease of use and cost efficiency for routine monitoring.

References

1. European Commission Regulation No. 589/2014, Official Journal of the European Union (2014).
2. van Bavel B., Geng D., Cherta L., Nácher-Mestre J., Portolés T., Ábalos M., Sauló J., Abad E., Dunstan J., Jones R., Kotz A., Winterhalter H., Malisch R., Traag W., Hagberg J., Ericson Jogsten I., Beltran J., Hernández F. Anal. Chem. 2015; DOI:10.1021/acs.analchem.5b02264.
3. Abad E., Saulo J., Caixach J., Rivera J. J. Chromatogr. A. 2000;893(2):383–391.
4. U.S. Environmental Protection Agency, Method 1613 for PCDD/Fs (1994).
5. EN 16215:2012, European Committee for Standardization.
6. European Commission Regulation (EU) No. 252/2012, Official Journal of the European Union.
7. European Commission Regulation (EU) No. 152/2009, Official Journal of the European Union.
8. Dunstan J., McCall E., Rao R., Ericson Jogsten I., van Bavel B. Waters Application Note No. 720005431en (June 2015).