Fast and Flexible Automated Sample extraction of PCDD/Fs and PCBs with X-TRACTION for Feed samples

Significance of the Topic

Persistent organic pollutants such as polychlorinated dibenzo-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) pose significant environmental and health risks due to their toxicity, persistence, and bioaccumulation potential. Reliable, rapid, and reproducible extraction methods are essential for routine monitoring and regulatory compliance in feed and food safety laboratories worldwide.

Objectives and Study Overview

This application note examines the performance of the LCTech X-TRACTION low-pressure fluid extraction (LPFE) system for automated extraction of PCDD/Fs and PCBs from various feed matrices. A series of quality-control feed samples were extracted using X-TRACTION and benchmarked against conventional Soxhlet extraction to assess accuracy, precision, solvent consumption, and processing time.

Methods and Instrumentation

The study utilized the following instrumentation and consumables:

• X-TRACTION extraction unit with 75 mL cells, glass fiber filters, stainless steel frits, and fraction vials.
• DEXTech silica, alumina, and carbon cleanup modules for post-extraction cleanup.
• D-EVA automated evaporation system for solvent concentration.
• Thermo Fisher DFS high-resolution mass spectrometer coupled to a gas chromatograph with SSL and PTV injectors for final quantification.

Extraction cells were loaded with homogenized feed (5–20 g) mixed with sodium polyacrylate, ensuring a dry, free-flowing matrix and a 2 cm air gap. LPFE runs comprised three cycles at 100 °C with 10 min hold times, using a hexane/acetone mixture. Extracts underwent automated cleanup and were evaporated to a known volume before HR-GC-MS analysis.

Key Results and Discussion

Comparison against nine replicate Soxhlet extractions demonstrated that X-TRACTION delivered equivalent accuracy with mean deviations within ±5.5 % for WHO-PCDD/F-TEQ and ±2.6 % for total non-dioxin-like PCB levels. Reproducibility across four independent LPFE runs showed relative standard deviations (RSDs) of 0.3–9.8 % for individual congeners. Extraction times were reduced from multiple hours to approximately 45 minutes per sample, and solvent use decreased by over 80 %.

Benefits and Practical Application of the Method

• Substantial reduction in extraction time and solvent consumption compared to Soxhlet.
• High throughput capability with up to six parallel LPFE units.
• Enhanced instrument longevity due to low operating pressures (≤17 bar).
• Automated, user-friendly workflow minimizes manual handling and potential contamination.

Future Trends and Opportunities

The LPFE approach can be extended to other persistent organic pollutants such as PBDEs, PCNs, and PFOS. Integration with online cleanup and direct injection into HR-GC-MS will further streamline workflows. Advances in miniaturized, high-pressure systems and green solvent alternatives are expected to enhance sustainability and scalability for routine regulatory monitoring.

Conclusion

The LCTech X-TRACTION system provides a fast, reliable, and low-pressure automated extraction solution for PCDD/F and PCB analysis in feed. It achieves comparable accuracy and precision to Soxhlet extraction while significantly reducing processing time, solvent use, and instrument wear, meeting the demands of modern high-throughput laboratories.

Reference

1. Bernsmann T., Albrecht M., Fürst P. Organohalogen Compounds 2016;78:797–799.
2. Calaprice C., Calvano C.D., Zambonin C., Focant J.F. Organohalogen Compounds 2015;77:733–735.
3. Bernsmann T., Albrecht M., Fürst P. Organohalogen Compounds 2014;76:1281–1284.