Polycyclic Aromatic Hydrocarbon (PAH) Evaluation in Fatty Food Matrix using Gas Chromatography Triple Quadrupole Mass Spectrometry (GC-MS/MS)

Significance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic contaminants formed during high-temperature processing of fatty foods. Due to their potential carcinogenicity and strict regulatory limits, accurate detection of PAHs in complex food matrices is vital for food safety laboratories, quality control, and regulatory compliance.

Study Objectives and Overview

This study evaluates a combined sample-cleanup strategy using Enhanced Matrix Removal–Lipid (EMR-Lipid) in conjunction with PSA/C18 dispersive solid-phase extraction (dSPE), followed by gas chromatography–triple quadrupole mass spectrometry (GC-MS/MS). The goal is to optimize recovery, reduce lipid interference, and achieve reliable quantification of four EU-regulated PAHs (benzo[a]pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene) at trace levels (1 ppb) in various fatty food matrices.

Methodology and Instrumentation

Sample Preparation:

• Homogenize sample and spike with PAH standards at 1 ppb
  
• Extract with acetonitrile and salt out with NaCl/MgSO4
  
• Clean up with EMR-Lipid sorbent and PSA/C18 in dSPE format
  
• Vortex, centrifuge, concentrate under nitrogen, and reconstitute in solvent

Instrumental Analysis:

• GC System: Agilent 7890 GC equipped with backflush capability to remove heavy residues between injections
• Column: DB-EUPAH UI, 25 m × 0.25 mm, 0.25 µm film thickness, optimized for PAH isomer separation
• Ion Source: Self-Cleaning Ion Source (SCIS) with hydrogen purge to prevent PAH deposition
• MS Detector: Agilent 7010 triple quadrupole MSD operating in EI mode, collision energy 50 eV
• Temperature Program: 60 °C (1 min) to 200 °C at 25 °C/min, then to 335 °C at 8 °C/min (hold 11 min)
• Injection: Pulsed splitless (20 psi for 0.9 min) at 320 °C, liner with glass wool

Main Results and Discussion

• EMR-Lipid combined with PSA/C18 achieved superior lipid removal and lowest baseline noise across diverse matrices (smoked sirloin, chocolate, brisket, vegetable oil, oysters).
• Recoveries for all four PAHs averaged 85–110% with relative standard deviations below 15% at 1 ppb.
• SCIS prevented source fouling, maintaining signal stability over extended sequences.
• Backflush preserved column performance by purging matrix residues between runs.
• Method compliance with EU Commission 1881/2006 levels demonstrated reliable detection well below maximum limits.

Benefits and Practical Applications

• High lipid removal efficiency minimizes matrix effects and extends instrument uptime.
• Robust quantification of trace PAHs in fatty foods supports regulatory compliance.
• Wide applicability to a range of matrices enhances laboratory throughput.
• SCIS and backflush features reduce maintenance frequency and operating costs.

Future Trends and Opportunities

• Integration of automated sample-prep platforms for higher throughput.
• Development of novel sorbents targeting emerging lipid contaminants.
• Coupling with high-resolution MS for non-target screening of PAH derivatives.
• Application of machine-learning algorithms to predict matrix effects and optimize cleanup protocols.

Conclusion

The combined EMR-Lipid/PSA-C18 cleanup with GC-MS/MS employing SCIS and backflush delivers a robust, sensitive, and reproducible method for trace PAH analysis in complex fatty food matrices. This approach meets stringent regulatory requirements and offers practical advantages in routine food safety testing.

Reference

• European Commission. Commission Regulation (EC) No 1881/2006 setting maximum levels for certain contaminants in foodstuffs.
• Anderson K.A., Szelewski M.J., Wilson G., Quimby B.D., Hoffman P.D. Modified ion source triple quadrupole mass spectrometer gas chromatograph for PAH analyses. J. Chromatogr. A 1419 (2015) 89–98.
• Agilent Technologies. Application Note 5991-3003EN: Optimized PAH Analysis using the Agilent Self-Cleaning Ion Source and the Enhanced PAH Analyzer.
• Agilent Technologies. Application Note 5991-6088EN: PAH analysis in Salmon with Enhanced Matrix Removal.