Quantitative detection of low levels of dioxins for food and feed safety using the EVOQ GC-TQ

Significance of the Topic

Dioxins and furans are highly toxic persistent organic pollutants regulated under EU legislation for food and feed safety due to their adverse effects on human and animal health.
Reliable quantification at ultra-trace levels is essential to enforce maximum levels in various matrices while addressing the cost and complexity limitations of high resolution techniques.

Objectives and Overview of the Study

The study aimed to validate a GC-MS/MS method using the Bruker EVOQ GC-TQ system to detect and quantify PCDD and PCDF congeners in complex food, feed and environmental samples according to EU Regulations EC 1881/2006 and 644/2017.
Key goals included demonstrating chromatographic separation of isomers, sensitivity in the femtogram range, compliance with performance criteria, and comparison with GC-HRMS results.

Methodology

Sample preparation involved solid-phase extraction of reference materials and doped animal feed.
Quantitation was performed by isotope dilution using 13C-labeled standards following EPA 1613.
Data acquisition used dynamic multiple reaction monitoring with two precursor ions and specific MRM product ions per congener.

Used Instrumentation

• Gas chromatograph: Bruker 436 GC with BR-Dioxins capillary column (60 m x 0.25 mm, 0.25 µm film)
• MS detector: Bruker EVOQ GC-TQ triple quadrupole, lens-free elliptical ion path, axial ion source, curved collision cell, orthogonal EDR detector
• Carrier gas: Helium, constant flow 1.5 mL/min
• Injector: Splitless pulsed injection at 280 °C, 1 µL volume
• MS conditions: Electron impact ionization at 280 °C, collision gas argon, resolution Q1/Q3 ≤ 0.7 amu, EDR scan

Main Results and Discussion

The method achieved clear separation of all 17 PCDD/PCDF congeners, including critical isomer pairs, with peak resolution better than regulatory criteria.
Limits of detection and quantitation were experimentally determined in the low femtogram range on-column, meeting S/N>3 and LOQ=1/5 of maximum levels.
Calibration curves showed excellent linearity (R2>0.99, RSD<13%).
Precision and recoveries were within regulatory limits (RSDr <15%, internal standard recoveries 60-120%).
Analyses of certified milk powder, fly ash and sewage sludge reference materials yielded concentrations within ±20% of certified values and comparable to GC-HRMS data.
Instrumental ion ratio stability and retention time reproducibility supported high confidence in target confirmation.

Benefits and Practical Applications of the Method

• High sensitivity and selectivity enable routine ultra-trace monitoring in food, feed, and environmental matrices.
• Lower operational cost and simplified maintenance compared to GC-HRMS make it suitable for routine laboratories.
• Automated QC scoring in Compass TQ software expedites data review and compliance reporting.
• Versatility across diverse sample types ensures protection of public and animal health under current EU regulations.

Future Trends and Potential Applications

• Integration with high-throughput sample preparation for large-scale monitoring programs.
• Extension to additional persistent organic pollutants and emerging contaminants.
• Synergy with advanced data analytics and machine learning for rapid screening.
• Hybrid workflows combining GC-MS/MS with novel ionization sources for broadened scope.

Conclusion

The EVOQ GC-TQ system provides a robust, high-sensitivity GC-MS/MS workflow that fully meets EU confirmatory criteria for dioxin analysis. It offers comparable performance to GC-HRMS at reduced cost and complexity, supporting routine monitoring of toxic PCDDs and PCDFs in regulatory, environmental and industrial laboratories.

References

• Regulation EC 1881/2006 setting maximum levels for dioxins and PCBs in foodstuffs
• Regulation EU 2017/644 and 2017/771 on confirmatory methods by GC-HRMS or GC-MS/MS
• WHO toxic equivalency factors for dioxins and dioxin-like PCBs
• EPA Method 1613 for 2,3,7,8-substituted PCDD/PCDF congeners by isotope dilution