Quantification of PAHs below regulatory limits in food using the EVOQ GC-TQ

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental and food contaminants with known carcinogenic properties. Their lipophilic nature and formation during heat processing lead to accumulation in food matrices, posing significant health risks. Stringent regulatory limits require sensitive analytical methods to ensure consumer safety and compliance.

Objectives and Study Overview

This study demonstrates the quantification of four regulated PAHs (benzo[a]pyrene, chrysene, benzo[b]fluoranthene, benz[a]anthracene) below EU maximum levels in various food matrices. Using a robust isotope dilution approach, the method covers 20 PAHs, aligning with EU and US EPA recommendations. Emphasis is placed on method performance, sensitivity, and regulatory compliance.

Methodology and Instrumentation

Sample Preparation

• Freeze-drying of 10 g food samples and determination of water content.
• Pressurized liquid extraction using hexane/acetone (50/50) on ASE with celite and florisil.
• SPE cleanup on Envi Chrom-P cartridges; elution with cyclohexane/ethyl acetate (40/60).

Instrumentation

• Gas chromatograph (Bruker 436 GC) coupled with EVOQ GC-TQ triple quadrupole MS.
• Agilent J&W Select PAH 30 m × 0.25 mm × 0.15 μm column; helium carrier gas at 1.30 mL/min.
• Injector at 280 °C, splitless mode; 2 µL injection volume.
• Oven program from 110 °C to 340 °C with gradient rates (60 °C/min to 3 °C/min).
• Electron impact ionization at 70 eV; SRM acquisition with optimized collision energies.

Main Results and Discussion

Calibration curves for the four PAHs exhibited excellent linearity (R² > 0.9999) over 5–2000 pg/µL. Signal-to-noise ratios of 40–55 at the lowest calibration point (5 pg/µL) confirmed method sensitivity. Analysis of a smoked meat sample yielded benzo[a]pyrene at 0.06 µg/kg and a PAH4 sum of 0.52 µg/kg, far below EU limits (2 µg/kg for benzo[a]pyrene, 12 µg/kg for PAH4). These results demonstrate quantification capabilities 20–30 times lower than regulatory thresholds.

Benefits and Practical Applications

• High sensitivity allows reliable detection of trace PAHs in complex food matrices.
• Isotope dilution ensures accurate quantification and compensates for matrix effects.
• SRM specificity reduces false positives and improves confidence in compliance testing.
• Applicable across diverse food types, including smoked products and oils.

Future Trends and Applications

Advances may include expanded PAH panels, integration with automated sample preparation, and high-throughput workflows. Further coupling with ion mobility or high-resolution MS could enhance selectivity. Emerging data analytics and chemometric tools may improve risk assessment and regulatory monitoring.

Conclusion

The EVOQ GC-TQ system combined with pressurized liquid extraction and SPE cleanup offers robust, sensitive, and specific quantification of regulated PAHs in food. Method detection limits significantly exceed requirements, supporting compliance with current EU regulations and ensuring consumer safety.

References

• Varlet A., Serot T., Monteau F., Le Bizec B. & Prost E. Determination of PAH profiles by GC–MS/MS in salmon processed by four cold-smoking techniques. Food Additives and Contaminants, 24 (2007) 744–757.
• Veyrand B. et al. Innovative method for determination of 19 PAHs in food and oil samples using GC–MS/MS based on isotope dilution. Journal of Chromatography A, 1149 (2007) 333–344.
• Veyrand B. et al. Human dietary exposure to PAHs: Results of the second French Total Diet Study. Environment International, 54 (2013) 11–17.
• Commission Regulation (EU) No 835/2011 amending Regulation (EC) No 1881/2006 regarding maximum levels for PAHs in foodstuffs.
• EU Commission Decision 2002/657/EC concerning method performance and result interpretation.