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 food and the environment, posing serious health risks. Regulatory agencies worldwide mandate confirmatory analysis at low levels. Recent EU Regulation 589/2014 authorized GC-MS/MS as a confirmatory method, offering a cost-effective alternative to high-resolution mass spectrometry.

Study objectives and overview

This inter-laboratory study evaluated the performance of Waters Atmospheric Pressure Gas Chromatography (APGC) coupled with the Xevo TQ-S tandem quadrupole mass spectrometer across four laboratories. Key goals were to compare sensitivity, selectivity, linearity, and accuracy of APGC-MS/MS against the established GC-EI-HRMS approach using various certified reference materials and real samples.

Applied Instrumentation

• GC: Agilent 7890A with DB-5MS or BPX-5 columns, pulsed splitless or PTV injection.
• Ion source: Waters APGC operating under dry charge-transfer conditions.
• MS: Xevo TQ-S in MRM mode; MassLynx v4.1 and TargetLynx for data acquisition and processing.

Methodology

Certified standards (EPA-1613 series) and 13C-labeled internal standards were used for calibration and quantification. Sample preparation followed established methods for milk powder, sewage sludge, fly ash, blood, fish and proficiency test materials. MRM transitions monitored molecular ions ([M+•] of 2,3,7,8-substituted congeners) with optimized collision energies (30–40 eV). Linearity was assessed across 0.1–40 pg/µL, and instrument performance was benchmarked against EPA 1613 and EN 16215 quality criteria.

Main results and discussion

• Sensitivity: Limits of quantification of 10–30 fg on column for 2,3,7,8-TCDD/TCDF, with signal-to-noise ratios >50 at 10 fg.
• Linearity: R² values above 0.998; relative response factor RSDs below 15%.
• Selectivity: Ion abundance ratios matched calibration standards within ±15%.
• Precision: Injection repeatability <15% at 10 fg; reproducibility across four labs met inter-laboratory criteria.
• Inter-lab comparison: APGC-MS/MS results agreed with GC-HRMS within ±7% across diverse matrices.

Benefits and practical applications

The APGC-MS/MS workflow delivers regulatory compliance for dioxin analysis with a benchtop system that is easier to operate and maintain than HRMS. It supports rapid throughput, flexible conversion between gas and liquid chromatography, and robust performance for food safety, environmental monitoring, and quality control laboratories.

Future trends and possibilities

• Extension of APGC-MS/MS to other persistent organic pollutants (PCBs, PAHs).
• Automation of sample preparation and data processing for higher throughput.
• Integration with high-resolution time-of-flight or Orbitrap analyzers for screening and confirmation.
• AI-driven spectral deconvolution and ion ratio validation for improved selectivity.

Conclusion

This inter-laboratory evaluation confirmed that APGC coupled to Xevo TQ-S meets the sensitivity, selectivity, and accuracy requirements of EU Regulation 589/2014 and provides a practical alternative to GC-EI-HRMS for confirmatory dioxin analysis in food and environmental samples.

References

1. European Commission Regulation (EU) No 589/2014.
2. van Bavel B. et al. Analytical Chemistry, 2015; DOI:10.1021/acs.analchem.5b02264.
3. Abad E. et al. Journal of Chromatography A, 2000;893(2):383–391.
4. U.S. EPA Method 1613, 1994.
5. EN 16215:2012, European Committee for Standardization.
6. European Commission Regulation (EU) No 252/2012.
7. European Commission Regulation (EU) No 152/2009.
8. Dunstan J. et al. Waters Application Note 720005431EN, 2015.