Fast and Accurate GC/MS Testing for EPA and EU Polycyclic Aromatic Hydrocarbons (PAHs) for Food andEnvironmental Applications - GC column Choices and Method Optimization

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants with known carcinogenic properties. They form during incomplete combustion of organic matter and can accumulate in food commodities, such as smoked meats, fish, oils and fats. Accurate, high‐throughput analysis of PAHs is essential to ensure consumer safety and comply with stringent EPA and EU regulatory limits.

Objectives and Overview of the Study

This work presents an optimized approach for selecting gas chromatography (GC) columns and coupling with GC/MS testing to achieve fast, reliable determination of priority PAHs under EPA Method 8310 and EU PAH4/PAH8 regulations. Key aims include:

• Reviewing regulatory target lists (EPA 16, EU PAH(15+1), PAH8, PAH4).
• Identifying chromatographic challenges for isomeric PAHs.
• Evaluating specialty stationary phases for improved separation at high temperatures.

Methodology

An analytical workflow was demonstrated using QuEChERS extraction of PAHs from fish matrix and GC/MS in selected ion monitoring (SIM) mode. Critical parameters:

• Column screening: various phenyl/arylene siloxane phases, liquid crystalline phases.
• Operating conditions: temperature ramps to >320 °C to elute high‐boiling PAHs.
• Detection: SIM transitions for key mass fragments (m/z 178–302).

Instrumentation

The optimized system comprised:

• Agilent 6890/6890N GC with programmable temperature vaporizing (PTV) injector.
• Agilent J&W Select PAH column (15 m × 0.15 mm × 0.10 µm) or DB-EUPAH (20 m × 0.18 mm × 0.14 µm).
• Agilent 5973 MSD in EI mode at 70 eV, source 300 °C, transfer line 280 °C.
• Helium carrier gas at constant flow (1.2 mL/min).

Key Results and Discussion

The phenyl/arylene-modified siloxane phase delivered:

• Baseline separation of critical isomer pairs: phenanthrene/anthracene, chrysene/triphenylene, benzo(b/j/k)fluoranthenes, indeno(cd)pyrene/dibenz(a,h)anthracene.
• Low bleed at 320 °C, yielding high signal-to-noise ratios and accurate quantitation.
• Complete elution of 16 EPA PAHs within 10 min.
• Column lifetimes averaging 1 000 injections (~2–4 months) in complex food matrices.

Benefits and Practical Applications

The optimized GC/MS method offers:

• Rapid analysis throughput for routine QA/QC laboratories.
• Robust performance under high‐temperature conditions.
• Compliance with both EPA and EU maximum levels (e.g., PAH4 sum limits in oils, smoked products, seafood).
• Enhanced resolution of isomeric PAHs to minimize quantitation bias.

Future Trends and Potential Applications

Ongoing developments may include:

• Miniaturized columns (narrower IDs, thinner films) to further reduce analysis time.
• Two-dimensional GC (GC×GC) for ultra-complex sample separations.
• High-resolution MS for improved selectivity without extensive chromatographic separation.
• Automation of extraction and cleanup (e.g., QuEChERS, online SPE) to streamline workflows.

Conclusion

Specialized PAH GC columns based on phenyl/arylene siloxane chemistries significantly improve separation of critical isomeric pairs at elevated temperatures, enabling fast, accurate GC/MS quantitation of regulated PAHs in food. This approach harmonizes with both EPA and EU methods, delivering robust lifetime performance and enhanced laboratory productivity.

References

Scientific Opinion of the Panel on Contaminants in the Food Chain on Polycyclic Aromatic Hydrocarbons in Food. The EFSA Journal (2008) 724
EPA Method 8310: Determination of Polycyclic Aromatic Hydrocarbons in Edible Oils, Fats, and Food Products
Agilent Application Notes on Select PAH and DB-EUPAH Columns