Using GC-MS/MS as a Confirmatory Method for Dioxin-Like PCBs in Food and Feed

Significance of the Topic

Persistent organic pollutants such as dioxin-like polychlorinated biphenyls (DL-PCBs) pose serious human health and environmental risks due to their high toxicity, persistence and ability to bioaccumulate in food chains. Regulatory bodies in the European Union set strict maximum (ML) and action levels (AL) for DL-PCBs in food and feed, expressed in toxic equivalence quotients (TEQs). Sensitive and selective confirmatory methods are essential to ensure compliance, protect consumers and maintain environmental safety.

Objectives and Overview of the Study

This study evaluates the analytical performance of the Thermo Scientific™ TSQ™ 8000 Evo triple-quadrupole GC-MS/MS system as a fully confirmatory technique for the quantification of the 12 regulated DL-PCB congeners in food and feed matrices. The method was tested on solvent standards and six extracted sample types and benchmarked against traditional gas chromatography–high-resolution mass spectrometry (GC-HRMS) data.

Methodology

Sample Preparation

• Feed samples cleaned using PowerPrep SPE system.
• Milk powder, adipose tissue and fish matrices processed by multilayer silica, basic alumina and carbon column clean-up.
• Final extracts prepared in nonane.

GC Conditions

• Thermo Scientific TRACE 1310 GC with single-taper SSL liner (1 µL splitless injection).
• Helium carrier gas at 1.2 mL/min.
• Oven program: 120 °C (2 min) → 250 °C at 25 °C/min → 285 °C at 2.5 °C/min → 320 °C (8 min).

MS/MS Conditions

• Thermo Scientific TSQ 8000 Evo triple-quadrupole, unit mass resolution.
• Electron ionization at 40 eV; source 300 °C; transfer line 280 °C.
• Argon collision gas at 60 psi; collision energies optimized by AutoSRM.
• Timed-SRM acquisition with two transitions per congener, ≥12 points/peak.
• Data processed in TargetQuan 3.1 with isotope-dilution calibration and automatic TEQ calculation.

Main Results and Discussion

Chromatographic separation of all 12 DL-PCB congeners was achieved with <10 % valley resolution even at the lowest standard (1 pg/µL). Method detection limits (LOQs) ranged from 0.10 to 0.41 pg/µL, meeting the one-fifth ML requirement. Calibration exhibited linear response from 1 to 2000 pg/µL, with relative standard deviations of average response factors below 6 %. Quantification in adipose tissue, fish liver, fish oil, dry fish, feed and milk powder showed excellent agreement with GC-HRMS results (deviations <3 %). All measured ion ratios fell within ±15 % of the calibration values, satisfying EU confirmation criteria.

Benefits and Practical Applications

• High sensitivity and selectivity comparable to GC-HRMS for routine monitoring of DL-PCBs.
• Faster cycle times and reduced operating costs relative to high-resolution sector instruments.
• Fully compliant with European Commission performance criteria.
• Integrated software streamlines quantitation, TEQ reporting and quality control.
• Applicable to a wide range of food and feed matrices for regulatory surveillance and quality assurance.

Future Trends and Applications

• Expansion to additional persistent organic pollutants and emerging contaminants.
• Integration of automated sample preparation and on-line clean-up.
• Development of novel column chemistries for enhanced isomer separation.
• Application of high-resolution MS and hybrid workflows for ultra-trace screening.
• Use of artificial-intelligence-driven data analysis to accelerate routine reporting.

Conclusion

The Thermo Scientific TSQ 8000 Evo GC-MS/MS platform delivers robust, reproducible and fully confirmatory analysis of DL-PCBs in complex food and feed matrices, meeting all EU regulatory requirements and offering an efficient alternative to GC-HRMS for routine monitoring.

References

1. European Commission, Commission Regulation No. 1883/2006, Off. J. Eur. Union, L320, 18–23.
2. European Commission, Commission Regulation No. 850/2004, Off. J. Eur. Union, L158, 7–49.
3. Travis C.C.; Hattemer-Frey H.A. Human Exposure to Dioxin. Sci. Total Environ. 1991, 104, 97–127.
4. Fries G.F. Role of Animal Products in Dioxin Exposure. J. Anim. Sci. 1995, 73, 1639–1650.
5. European Commission, Commission Regulation No. 102/2002, Off. J. Eur. Union, L6, 45–49.
6. Kotz A.; Malisch R.; Focant J.; et al. Analytical Criteria for Use of MS/MS for Dioxin-Like PCBs. Organohalogen Compd. 2012, 74, 156–159.
7. European Commission, Commission Regulation No. 252/2012, Off. J. Eur. Union, L84, 1–22.
8. European Commission, Commission Regulation No. 1259/2011, Off. J. Eur. Union, L320, 18–23.
9. Thermo Scientific Application Note 10380: Meeting the European Commission Performance Criteria for PCDD/Fs by Triple Quadrupole GC-MS/MS, 2015.