Automated Sample Preparation and Measurement Workflow for Dioxin Analysis

Importance of the Topic

Dioxins are persistent environmental pollutants with extremely high toxicity even at trace levels. Reliable detection in food and feed is critical to protect public health and comply with strict regulatory limits. Advances in automation and mass spectrometric sensitivity can transform routine monitoring workflows by reducing analysis time, labor, and solvent use while maintaining or improving detection limits.

Objectives and Study Overview

This study aimed to develop and evaluate a fully automated workflow for dioxin analysis in food and animal feed. Key goals included:

• Implementing automated extraction and purification to shorten sample preparation time from days to hours.
• Assessing a triple quadrupole GC-MS/MS system equipped with a Boosted Efficiency Ion Source (BEIS) for attogram-level sensitivity.
• Verifying method robustness and long-term stability across approximately 250 real-world samples representing 40 different matrices.

Methodology and Instrumentation

Sample preparation combined two automated modules:

• BUCHI SpeedExtractor for pressurized liquid extraction of organic residues from solid samples, achieving high recoveries via multiple extraction cycles and parallel processing of up to six samples.
• Miura GO-EHT purification system employing prepacked columns for lipid removal, sulfur and basic component elimination, and fractionation of dioxins and PCBs, using only 110 mL of solvents per run.

GC-MS/MS analysis was performed on a Shimadzu GCMS-TQ8050 NX with BEIS, using a SH-Rxi-5Sil MS capillary column (60 m × 0.25 mm I.D., 0.25 μm film). Key parameters:

• Injection: splitless, 10 μL hexane extract, 280 °C.
• Oven program and MS settings optimized for EU regulatory congeners, with ion source at 230 °C and interface at 300 °C.
• Automated retention time adjustment via AART function and reporting via integrated software tool.

Key Results and Discussion

The automated workflow yielded:

• Detection limits as low as 20 fg for 2,3,7,8-TCDD, comparable to or better than traditional HRMS systems.
• Analysis throughput increased dramatically, reducing total sample prep and measurement time from approximately 2 days to around 2 hours per batch.
• Consistent sensitivity and quantitation accuracy over dozens of sequential runs, demonstrating instrument durability and method robustness.

Benefits and Practical Applications

The integrated automation offers multiple advantages:

• Substantial reduction in labor and hands-on time, lowering operational costs.
• High sample throughput to support routine monitoring in QA/QC and regulatory laboratories.
• Reduced solvent consumption and waste generation, improving sustainability.
• Rapid deployment via preconfigured method files, streamlining method validation and compliance.

Future Trends and Opportunities

Ongoing developments may include:

• Further integration with robotic sampling and AI-driven data processing to enhance throughput and decision making.
• Miniaturized extraction and microfluidic purification to decrease solvent use and sample size.
• Expansion to emerging contaminants and non-dioxin-like PCBs using similar automated workflows.

Conclusion

The fully automated sample preparation and GC-MS/MS workflow described here dramatically streamlines dioxin analysis, delivering femtogram-level sensitivity with high throughput and reproducibility. This approach offers a practical and cost-effective solution for routine environmental and food safety monitoring, meeting stringent regulatory demands while reducing labor and solvent usage.

References

1. Anderson H.E., Santos I.C., Hildenbrand Z.L., Schug K.A. Analytica Chimica Acta. 2019;1085:1–20.
2. Shimadzu Application News No. 01-00171-EN – Nexera Organic Acid Analysis System and its Application.
3. Shimadzu Technical Report C190-E237A – High-Speed Analysis of Organic Acids Using Shim-pack Fast-OA and pH-Buffered Electrical Conductivity Detection.