Analysis of Dioxins in Environmental Samples using GC/MS - Consumable Workflow Ordering Guide

Importance of the Topic

Dioxins and furans are among the most toxic persistent organic pollutants. They originate from industrial and natural high temperature processes and pose serious environmental and health risks due to bioaccumulation in fatty tissues and entry into food chains. Regulatory frameworks such as the Stockholm Convention and EPA standards require highly sensitive and reliable analytical methods to monitor their levels in environmental matrices.

Objectives and Study Overview

The primary goal of the study was to evaluate an alternative testing protocol for the analysis of 2,3,7,8-substituted tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans in environmental samples using gas chromatography coupled with tandem mass spectrometry. The SGS Axys Method 161305 was benchmarked against traditional high resolution GC/HRMS techniques outlined in EPA Method 1613B and related protocols.

Methodology

The method employs isotope dilution for accurate quantitation of target congeners extracted from waters, soils, and biosolids. GC separation follows a multi-step temperature program optimized for resolution of closely eluting isomers and critical TEQ-relevant compounds. Key performance metrics include peak valley height ratios, total run time, and compliance with regulatory criteria.

Instrumentation Used

• Gas chromatograph Agilent 7890B with splitless injection and a 60 m DB-5 capillary column
• Triple quadrupole mass spectrometer Agilent 7010B operated in electron ionization and multiple reaction monitoring
• Helium carrier gas in constant flow mode
• Nitrogen collision gas and helium quench gas

Main Results and Discussion

Comparative analysis of real-world biosolids showed that GC/TQ and GC/HRMS deliver equivalent total PCDD/F concentrations within analytical uncertainty. The valley height criterion between 2,3,7,8-substituted isomers was satisfied, with front and rear valley height to peak height ratios of 20.4 % and 7.8 %, both below the 25 % threshold set by EPA Method 1613B. Use of an ultra inert DB-5ms column further enhanced peak symmetry and isomer separation, validating the robustness of the GC/TQ approach.

Benefits and Practical Applications of the Method

• Significant instrument and operational cost savings compared to high resolution MS systems
• Reduced maintenance complexity and training requirements
• Full compliance with EPA performance standards for dioxin and furan analysis
• High sensitivity and specificity for low-level environmental monitoring

Future Trends and Opportunities

Broader adoption of GC/TQ platforms for persistent organic pollutant analysis is anticipated, driven by evolving column chemistries for enhanced selectivity and automation to increase sample throughput. Emerging hybrid MS technologies may further improve sensitivity while simplifying workflows. Expansion into multi-residue methods will enable comprehensive screening of environmental contaminants in a single analytical run.

Conclusion

The SGS Axys Method 161305 using GC/TQ offers a cost-effective and reliable alternative to GC/HRMS for the determination of PCDDs and PCDFs in environmental samples. It meets stringent EPA performance criteria, reduces operational expenses, and achieves comparable accuracy and precision, supporting routine monitoring under global regulatory frameworks.

References

• U.S. EPA Method 1613B for PCDDs and PCDFs by isotope dilution HRGC/HRMS
• U.S. EPA Method 8280B for PCDDs and PCDFs by HRGC/LRMS
• U.S. EPA Method 8290A for PCDDs and PCDFs by HRGC/HRMS
• U.S. EPA Method 234 for dioxins and furans from stationary sources
• An Alternate Testing Protocol for EPA 1613B using Agilent Triple Quadrupole GC/MS