Confirmation of PCDDs and PCDFs at Sub-Femtogram Levels Using Atmospheric Pressure Gas Chromatography (APGC) with Xevo TQ-XS

Importance of the Topic

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are persistent organic pollutants regulated internationally due to their toxicity and bioaccumulation. Monitoring their levels at ultra-trace concentrations in environmental and food samples is essential to protect public health and comply with the Stockholm Convention and regional regulations.

Goals and Study Overview

This study aimed to establish detection limits for PCDDs and PCDFs using advanced chromatography and mass spectrometry in solvent standards, and to validate accurate quantitation in a certified fly ash reference sample for quality control purposes.

Methodology and Instrumentation

The analysis combined Atmospheric Pressure Gas Chromatography (APGC) with a Xevo TQ-XS tandem quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode.

• TCDD-specific method: Agilent DB-5MS column (30 m × 0.25 mm, 0.25 µm) with helium carrier gas at 1 mL/min; Agilent 7890A GC oven; pulsed splitless injection at 290 °C; temperature ramp from 130 °C to 320 °C.
• Comprehensive PCDD/F method: Zebron ZB-5MS column (60 m × 0.25 mm, 0.25 µm) at 1.4 mL/min; similar injector conditions; multi-stage temperature program up to 320 °C over 49.85 min.
• APGC source parameters: corona pin 2.0 µA; cone gas 260 L/h; auxiliary gas 200 L/h; makeup gas 300 mL/min; quadrupole resolution 0.7 Da.
• Calibration range covered 100 ag to 100 pg on-column for 2,3,7,8-TCDD, using two MRM transitions.

Main Results and Discussion

• Linearity: Excellent linear response for 2,3,7,8-TCDD across five orders of magnitude (100 ag–100 pg).
• Reproducibility: 100 fg injections over 20 days (1000 injections) yielded an RSD of 9.2% and stable isotope ratios (≤15%).
• Isotope Ratios: Consistent ratio measurements across serial dilutions of EPA 1613 standards confirm reliable congener identification required by legislation.
• Fly Ash Sample: Complex matrix analysis demonstrated clear detection and accurate quantitation of 2,3,7,8-TCDD matching certified QC values.

Benefits and Practical Applications of the Method

• Sub-femtogram detection capability allows sample and standard dilution, reducing material costs.
• Minimized sample preparation and pre-concentration steps accelerate throughput.
• High robustness and reproducibility support long batch runs without performance loss.
• Compliance with stringent regulatory requirements for dioxin analysis.

Future Trends and Potential Applications

Ongoing improvements may include automated sample handling, integration with high-resolution mass spectrometry for expanded pollutant screening, and miniaturized APGC systems for field-deployable monitoring. Enhanced data processing algorithms and AI-driven workflows could further optimize sensitivity and throughput.

Conclusion

APGC coupled with the Xevo TQ-XS provides an exceptionally sensitive and reliable platform for trace dioxin and furan analysis in complex matrices, exceeding current regulatory performance criteria and offering significant operational advantages in environmental and food safety laboratories.

Reference

1. United Nations Treaty: Stockholm Convention of Persistent Organic Pollutants, 2001.
2. Dunstan J., Hall K., Douce D., et al. A Confirmatory Method for PCDD/Fs in Compliance with EU Regulation 589/2014/EU Using APGC with Xevo TQ-S. Waters Application Note 720005431en, 2015.
3. EN 16215:2012 European Standard for dioxins analysis. CEN, 2012.
4. EU Commission Regulation 589/2014: Methods for sampling and analysis of dioxins and PCBs in foodstuffs.
5. EPA Method 1613 (Revision B). US EPA, Washington, DC, 1994.