A Confirmatory Method for PCDDs and PCDFs in Compliance with EU Regulation 589/2014/EU Using Atmospheric Pressure Gas Chromatography (APGC) with Xevo TQ-S

Significance of the Topic

The detection of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in food and feed is critical due to their toxicity, persistence, and strict regulatory limits imposed by the European Commission and international conventions.
Accurate confirmatory methods are essential to ensure compliance with Regulation 589/2014/EU and protect public health.

Objectives and Study Overview

This study aims to validate an atmospheric pressure gas chromatography (APGC) coupled to a Xevo TQ-S tandem quadrupole mass spectrometer (GC-MS/MS) method for confirmatory analysis of 17 2,3,7,8-substituted PCDD/F congeners in food and feed.
The method’s performance is assessed against specificity, sensitivity, selectivity, linearity, ion ratio, and quantification criteria defined in Regulation 589/2014/EU.

Methodology and Instrumentation

Atmospheric Pressure Gas Chromatography with charge transfer ionization (APGC) was interfaced to a Xevo TQ-S mass spectrometer operating in Multiple Reaction Monitoring (MRM) mode.
GC conditions included a 60 m × 0.25 mm DB-5MS UI column, pulsed splitless injection, and a temperature program from 140 °C to 300 °C.
APGC source parameters comprised API+ ionization at 150 °C source temperature, 30 V cone voltage, nitrogen cone gas, and argon collision gas at 5 × 10⁻³ mbar.
Seventeen native PCDD/F congeners and corresponding 13C-labeled internal standards were used to build calibration curves spanning 0.01 to 40 pg/μL on column.
Sample preparation followed EU Regulations 252/2012/EC and 152/2009/EC.

Major Results and Discussion

Specificity and Selectivity:

• Unit mass resolution in both quadrupoles differentiated target analytes from matrix interferences.
• Two selective MRM transitions per congener complied with Annex III ion criteria.

Sensitivity:

• Limits of quantification reached low femtogram levels, with 10 fg on column achieving peak-to-peak S/N of 49.

Ion Ratio Compliance:

• Measured precursor–product ion ratios for 35Cl/37Cl pairs were within the ±15 % tolerance across standards and samples.

Linearity:

• Calibration exhibited excellent linearity (R² > 0.995) over seven concentration points from 0.01 to 40 pg/μL.

Method Comparison:

• Mixed animal fat samples analyzed by both APGC-MS/MS and GC-HRMS showed close agreement in total Toxic Equivalents (TEQs), confirming method equivalence.

Benefits and Practical Applications

The APGC-MS/MS platform provides a sensitive, selective, and robust alternative to high-resolution MS for dioxin confirmation.
Low injection volumes (1 μL) minimize contamination, extend column and source lifetime, and reduce maintenance.
Automated data processing via TargetLynx streamlines ion ratio checks and compliance flagging, enhancing laboratory efficiency.

Future Trends and Applications

Advances in soft ionization may further improve sensitivity and reduce in-source fragmentation.
Combining APGC with high-resolution MS or ion mobility spectrometry could expand detection of emerging persistent organic pollutants.
Machine-learning algorithms for automated peak identification and compliance assessment promise to accelerate routine monitoring.
Method adaptations for water, soil, and other matrices will broaden environmental and food safety surveillance.

Conclusion

The APGC-MS/MS confirmatory method on the Xevo TQ-S meets or exceeds all performance criteria stipulated by EU Regulation 589/2014/EU for PCDD/F analysis.
It delivers high specificity, low femtogram sensitivity, robust linearity, and reliable ion ratio confirmation, offering a viable alternative to GC-HRMS for food and feed safety laboratories.

References

1. Stockholm Convention on Persistent Organic Pollutants, United Nations, 2001.
2. WHO Re-evaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-like Compounds, 2005.
3. European Commission Regulation No. 589/2014/EU, Official Journal of the EU, L164, 2014.
4. European Commission Regulation No. 850/2004/EU, Official Journal of the EU, L158, 2004.
5. U.S. EPA Method 1613 for Dioxins, 1994.
6. EN 16215:2012, European Committee for Standardization, April 2012.
7. Portolés T., Cherta L., Beltrán J., Hernández F., J. Chromatogr. A 1260, 2012.
8. Ladak A., Organtini K.L., Dorman F.L., Waters Technology Brief No. 720004964EN, 2014.