Dioxins: Sensitive analysis of polychlorinated dibenzo-p-dioxins/furans using GC-MS with cost effective Helium saving technology

Significance of the topic

Trace-level detection of polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs) is essential for environmental monitoring and regulatory compliance under EU Directives 644/2017 and 771/2017. Achieving sub-picogram sensitivity with gas chromatography–tandem mass spectrometry (GC-MS/MS) ensures accurate risk assessment of persistent organic pollutants in soil and other matrices. Sustainable laboratory operation also requires minimizing helium consumption, which is scarce and costly.

Objectives and Overview of the Study

The study aimed to evaluate the analytical performance, robustness, and cost savings of the new iConnect™ HeSaver-H2Safer™ split/splitless (SSL) injector on a Thermo Scientific™ TSQ™ 9610 GC-MS/MS system for the analysis of PCDDs/PCDFs in soil extracts. Key goals included comparing helium usage, sensitivity at femtogram levels, and injection precision versus a standard SSL injector.

Methodology and Instrumentation

Sample preparation involved extraction of two-gram soil aliquots with acetonitrile/hexane followed by centrifugation, evaporation, and reconstitution in nonane with isotopically labeled standards (EPA-1613). A six-point calibration curve and LOQ check standards were prepared by serial dilution.

Instrumentation Used:

• Thermo Scientific TSQ 9610 GC-MS/MS with advanced electron ionization (AEI) source
• iConnect HeSaver-H2Safer SSL injector using nitrogen for split and purge lines
• TG-Dioxin capillary column (60 m × 0.25 mm, 0.25 μm)
• Thermo Scientific Chromeleon™ CDS with Dioxin Analyzer workflow

Operating conditions matched established methods for PCDD/F separation and detection, with a 1.5 μL injection volume.

Main Results and Discussion

The HeSaver-H2Safer module reduced helium use by a factor of eight compared to a conventional SSL injector, translating into over $1,000 annual savings for continuous operation. Repeated injections of spiked soil extracts (n=69 and n=31) yielded relative standard deviations below 9%, confirming stable performance over four days. Quantification accuracy across spiking levels (15–150 fg/µL) showed deviations within ±7.2 fg for most congeners. Limit of quantification checks demonstrated femtogram-level sensitivity (e.g., 5–5.7 fg for TCDD/F).

Benefits and Practical Applications

• Significant reduction in helium consumption lowers operational costs and supports sustainability goals
• Maintained or improved analytical sensitivity and precision at femtogram levels
• Robust performance in complex soil matrices without extensive cleanup
• Enables 24/7 compliance monitoring of PCDD/Fs in environmental and industrial laboratories

Future Trends and Possibilities

As gas scarcity and cost pressures intensify, adoption of mixed-gas injector technologies will grow. Further developments may include dynamic gas management systems, integration with hydrogen-based methods, and expansion to other trace-level contaminant analyses. Advances in ionization sources and data workflows will continue to enhance sensitivity and throughput.

Conclusion

The iConnect HeSaver-H2Safer SSL injector on a TSQ 9610 GC-MS/MS platform delivers robust, precise, and femtogram-level analysis of PCDDs/PCDFs while cutting helium use by eightfold. This approach combines regulatory-compliant sensitivity with substantial cost savings, positioning it as a valuable solution for sustainable environmental analytics.

References

1. Law R, Cojocariu C, Silcock P, Calaprice C. Thermo Scientific Application Note 10590. 2018.
2. Scollo G, Parry I, Cavagnino D. Thermo Scientific Technical Note 001218. 2022.