Utilizing cost effective helium saving technology for low level quantitation of Polychlorinated dibenzo-p- dioxins/furans using gas chromatograph mass spectrometry

Importance of the Topic

Polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs) are persistent environmental contaminants with high toxicity even at sub-picogram levels. Regulatory limits under EU frameworks require analytical methods capable of reliable detection and quantification at these trace concentrations. Sustainable solutions that maintain analytical performance while reducing operational costs and resource consumption are highly sought after in environmental and regulatory laboratories.

Objectives and Overview of the Study

• Demonstrate the sensitivity and robustness of a cost-effective helium-saving injector module (iConnect HeSaver-H2Safer) for GC-MS/MS analysis of PCDD/Fs.
• Compare helium consumption and analytical performance against a standard split/splitless injector.
• Assess method suitability for soil extracts without prior cleanup at femtogram levels.

Materials and Methods

• Sample Preparation: Two grams of soil were extracted with a 1:1 mixture of acetonitrile and hexane, centrifuged, evaporated, spiked with isotopic calibration standards, and reconstituted in nonane.
• Calibration: Six-level calibration curve prepared using EPA-1613 isotopically labeled standards, with additional LOQ check standards at one-half and one-quarter concentrations.
• Chromatography and Detection: Analyses performed on a Thermo Scientific TSQ 9610 GC-MS/MS system equipped with the iConnect HeSaver-H2Safer SSL injector, TG-Dioxin capillary column, and advanced electron ionization source. A 1.5 µL injection volume was used. Quantification employed isotopic dilution via Chromeleon software with the Dioxin Analyzer workflow.

Results and Discussion

• Helium Savings: The HeSaver-H2Safer injector reduced helium use by a factor of eight compared to a conventional injector, translating to over US$1,000 annual cost savings in continuous operation.
• Precision and Robustness: Over 100 injections of spiked soil extract across two separate runs showed relative standard deviations below 8% in peak area and concentration, with variation in recovered PCDD/Fs within ±7.2 fg.
• Sensitivity: Limits of quantification in the range of 0.01–0.1 pg µL⁻¹ were achieved, enabling accurate measurement of TCDD/F at 15 fg and PeCDD/F, HxCDD/F, HpCDD/F at 75 fg, and OCDD/F at 150 fg levels in matrix extracts.

Benefits and Practical Applications

• Maintains regulatory compliance by delivering fg-level quantitation with robust long-sequence performance in complex matrices.
• Significantly reduces helium consumption and operating expenses, supporting sustainable laboratory practices.
• Compatible with existing GC-MS/MS infrastructure, facilitating straightforward method adoption.

Future Trends and Applications

Laboratories are likely to embrace gas-saving injector technologies and alternative carrier gases to address helium scarcity. Continued advances in ion source design and data-processing workflows will further enhance sensitivity and throughput. Integration of real-time monitoring and predictive maintenance may optimize resource use and ensure method reliability.

Conclusion

The study confirms that the iConnect HeSaver-H2Safer SSL injector on a TSQ 9610 GC-MS/MS platform delivers high sensitivity and reproducibility for trace PCDD/F analysis while achieving substantial helium savings. This approach supports both regulatory requirements and sustainable laboratory operations.

Used Instrumentation

• Thermo Scientific TSQ 9610 GC-MS/MS system
• iConnect HeSaver-H2Safer split/splitless injector
• TG-Dioxin 60 m × 0.25 mm, 0.25 µm capillary GC column
• Advanced electron ionization (AEI) source
• Chromeleon Chromatography Data System with Dioxin Analyzer workflow

References

1. Law R, Schaechtele A, Gujar A, Xing J, Cojocariu C. Thermo Scientific Application Note 10703 (2019).
2. Scollo G, Parry I, Cavagnino D. Thermo Scientific Technical Note 001218 (2022).