PAH Analysis in Fish by GC/MS Using QuEChERS/dSPE Sample Preparation and High Efficiency GC Columns

Importance of the Topic

The Deepwater Horizon spill highlighted the need for reliable monitoring of polycyclic aromatic hydrocarbons (PAHs) in seafood. PAHs persist in the environment, bioaccumulate in fish tissue, and pose human health risks. Regulatory bodies such as NOAA and the US FDA set strict limits on PAHs in finfish, crustaceans, and mollusks to ensure consumer safety and guide fishery reopening decisions.

Objectives and Overview of the Study

This study presents a streamlined GC/MS method for analyzing 16 EPA-priority PAHs in fish. By combining QuEChERS/dSPE sample preparation with high-efficiency, ultra-inert GC columns, it aims to achieve low detection limits, robust recoveries, and high laboratory throughput.

Methodology and Instrumentation

Sample Preparation employs the QuEChERS protocol:

• Weigh 3 g of homogenized fish tissue; add surrogate/internal standards.
• Extract with acetonitrile, vortex and shake on a Geno/Grinder.
• Clean up via dispersive SPE (fatty sample dSPE tube) and centrifugation.
• Process up to 60 samples in an 8 h shift.

GC/MS Analysis conditions:

• System: Agilent 7890 GC coupled to 5975B MSD in SIM mode.
• Column: J&W DB-5ms UI, 20 m × 0.18 mm × 0.18 μm.
• Carrier gas: Helium at 1.7 mL/min; splitless injection (0.5 µL, 320 °C).
• Oven program: 50 °C hold, ramp to 315 °C with backflush enabled.

Main Results and Discussion

The ultra-inert DB-5ms UI column resolved all critical PAH pairs (e.g., phenanthrene/anthracene) with sharp peaks and minimal tailing. Calibration in matrix-matched standards (10–1000 ppb) was linear (R² > 0.995). Recoveries at 25, 250, and 500 ppb ranged from 80–139% with RSDs below 5%. The method limit of quantitation for benzo[a]pyrene was 10 ppb, well under regulatory concern levels.

Benefits and Practical Applications

• Rapid sample preparation reduces prep time from 12–14 h to under 20 min per sample.
• High throughput: up to 60 samples per shift with QuEChERS.
• Enhanced sensitivity and reproducibility via ultra-inert column technology.
• Meets or exceeds regulatory requirements for seafood PAH monitoring.

Future Trends and Opportunities

Advances may include further automation of QuEChERS workflows, integration with fast GC and high-resolution MS for greater selectivity in complex matrices, and miniaturized on-site screening tools for rapid environmental assessment.

Conclusion

This method demonstrates a cost-effective, sensitive, and robust approach for quantifying 16 priority PAHs in fish. QuEChERS/dSPE coupled with high-efficiency, ultra-inert GC columns achieves regulatory compliance, high throughput, and excellent analytical performance, supporting routine monitoring and risk assessment in seafood safety programs.

Used Instrumentation

• Agilent 7890A GC with 5975B MSD
• Agilent 7693 autosampler
• J&W DB-5ms Ultra Inert column (20 m × 0.18 mm × 0.18 μm)
• QuEChERS extraction and dispersive SPE kits