PCDD/F Screening at the Maximum Residue Level for Food Safety Analysis using Highly Selective Triple Quadrupole GC/MS/MS

Importance of the Topic

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants with high toxicity and bioaccumulation potential. Regulatory bodies worldwide have established maximum residue levels (MRLs) to protect consumer health. Reliable screening methods at femtogram levels are essential to monitor compliance in food matrices and to respond promptly to contamination events.

Objectives and Study Overview

This study introduces a sensitive screening technique targeting PCDD/Fs and PCBs at European MRLs in foodstuffs. It employs a triple quadrupole GC-MS/MS system with hyperbolic quadrupole rods to enhance selectivity and utilizes US EPA Method 1613A with isotope dilution quantification. The aim is to deliver a high-throughput, cost-effective approach for routine food safety control.

Applied Instrumentation

• Trace GC Ultra gas chromatograph with split/splitless injector and TRACE TR-Dioxin 5MS column (30 m, 0.25 mm ID, 0.1 µm film)
• TriPlus AS liquid autosampler
• TSQ Quantum XLS triple quadrupole MS with hyperbolic quadrupole rods

Methodology

Sample extracts were spiked with 13C-labelled internal standards prior to clean-up. GC conditions included a splitless injection of 2 µL, helium carrier gas at 0.8 mL/min, and a temperature program from 120 °C to 260 °C. MS parameters were optimized at 40 eV electron energy, 0.7 Da resolution in Q1 and Q3, and 2.0 mTorr argon collision gas. A sequential SRM scheme covered five time segments, each targeting two precursor ions and one product ion per congener from tetra- to octa-chlorinated species.

Main Results and Discussion

The method achieved mid-fg absolute detection limits and demonstrated reliable quantitation in complex matrices such as fish extracts. Five identification points per congener surpassed the EU requirement of four. The use of sequential SRM minimized false positives and provided high confidence at or below 100 fg injected. Representative fish sample analyses confirmed the method’s robustness and selectivity.

Benefits and Practical Applications

• High sample throughput for routine screening in food industry and regulatory labs
• Cost-effective alternative to HRMS for initial screening
• Reduced false positives compared to bioassays
• Applicable to diverse and challenging matrices

Future Trends and Potential Applications

Advances may include tighter integration with high-resolution MS for streamlined confirmatory workflows, automated sample preparation to further increase throughput, and incorporation of data analytics and AI for rapid pattern recognition and risk assessment. Expanding the analyte scope and miniaturizing instrumentation could further enhance field deployability.

Conclusion

The triple quadrupole GC-MS/MS approach using the TSQ Quantum XLS system provides a robust, sensitive, and selective screening platform for PCDD/Fs and PCBs in food at regulatory MRLs. It enables efficient monitoring, supports regulatory compliance, and reduces reliance on resource-intensive confirmatory methods.

Reference

1. COUNCIL REGULATION (EC) No 2375/2001 of 29 November 2001, Official Journal L321/1.
2. COMMISSION DIRECTIVE 2002/69/EC of 26 July 2002, Official Journal L209/5.
3. COMMISSION DECISION of 12 August 2002, Official Journal L221/8.
4. Krumwiede D., Huebschmann H.J., Confirmation of Low Level Dioxins and Furans in Dirty Matrix Samples using High Resolution GC/MS, Application Note 30112, 2008.
5. Krumwiede D., Huebschmann H.J., Analysis of PCBs in Food and Biological Samples Using GC Triple Quadrupole GC-MS/MS, Application Note 10262, 2008.