Determination of Ultratrace Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans Using GC/MS/MS

Significance of the Topic

PCDDs and PCDFs are highly toxic, persistent organic pollutants that accumulate in the environment and pose serious health risks. Detecting these compounds at ultratrace levels is essential for environmental monitoring, regulatory compliance, and risk assessment. Improved analytical methods help ensure accurate quantification in complex matrices and support strategies to control emissions from sources such as waste incineration.

Objectives and Study Overview

This study aims to develop and validate a GC/MS/MS method using an Agilent 7010 triple quadrupole system for the determination of seventeen 2,3,7,8-substituted PCDD/F congeners. The method is benchmarked against high-resolution mass spectrometry (GC/HRMS) and applied to certified reference materials and environmental fly ash samples. Key objectives include assessing sensitivity, selectivity, precision, and potential as a cost-effective alternative.

Methodology and Instrumentation

Instrumentation

• Gas chromatograph: Agilent 7890 GC
• Mass spectrometer: Agilent 7010 triple quadrupole GC/MS/MS with high-efficiency electron ionization
• Column: Agilent J&W DB-5ms UI, 60 m × 0.25 mm, 0.25 µm film thickness
• Injection: 1 µL splitless at 290 °C, helium carrier gas at 1.0 mL/min
• MS mode: Electron ionization at 70 eV, multiple reaction monitoring (MRM)

Sample Preparation

• Soxhlet or accelerated solvent extraction with n-hexane/dichloromethane (1:1)
• Cleanup using acidified silica gel, multilayer silica, and activated carbon columns
• Elution with toluene and concentration under nitrogen
• 13C-labeled internal standards added for quantification

Main Results and Discussion

Separation and Sensitivity

• Complete chromatographic separation of 17 PCDD/F congeners within 58 minutes
• Limits of detection between 0.008 and 0.08 pg/µL, demonstrating ultratrace capability
• Relative response factors (RRFs) with RSDs below 3% meet EPA method 1613 criteria

Method Validation

• Certified reference material (WMF-01 fish tissue) analysis yielded recoveries within certified ranges and RSDs below 10%
• Comparison with GC/HRMS on six fly ash samples (2.1–32.6 pg TEQ/g) showed strong agreement in total TEQ values

Benefits and Practical Applications

• High sensitivity and selectivity allow accurate quantification of PCDD/Fs in environmental and biological matrices
• GC/MS/MS system offers a cost-effective alternative to high-resolution instruments
• Suitable for regulatory compliance monitoring in food, feed, and waste samples
• Reduces analysis time and lowers operational complexity

Future Trends and Applications

• Integration of miniaturized sampling and on-site analysis platforms
• Advances in ionization and detector technologies to further lower detection limits
• Expansion to broader classes of persistent organic pollutants
• Automation and software enhancements for streamlined data processing and reporting

Conclusion

The developed GC/MS/MS method using the Agilent 7010 system demonstrates robust performance for ultratrace PCDD/F analysis. It achieves sensitivity and precision comparable to GC/HRMS while offering reduced operational costs. The approach is validated with reference materials and environmental samples, confirming its suitability for routine monitoring and regulatory compliance.

References

• Zheng G. J.; Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans Pollution in China: Sources, Environmental Levels and Potential Human Health Impacts. Environment International 2008, 34(7), 1050–1061.
• European Commission Regulation (EU) No 709/2014 amending Regulation (EC) No 152/2009 on dioxins and PCBs. 2014.
• Bhavasar S. P.; Converting Toxic Equivalents (TEQ) of Dioxins and Dioxin-Like Compounds in Fish From One Toxic Equivalency Factor (TEF) Scheme to Another. Environment International 2008, 34(7), 915–921.
• Riener J.; Validation of a Confirmatory GC/MS/MS Method for Dioxins and Dioxin-Like PCBs. Agilent Technologies Application Note 5991-6590EN, 2016.
• Method 1613, Tetra- Through Octa-Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS. US EPA, 1997.