Determination of PAH in Seafood: Optimized Sample Preparation Procedures for LC-Fluorescence Screening and GC-MS(MS) Confirmation

Significance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants with documented carcinogenic properties. Seafood can accumulate PAHs from water and sediments, posing health risks to consumers. Rapid and reliable detection in shellfish and finfish is critical for food safety control, regulatory compliance and public health protection.

Objectives and Overview

This study presents an optimized workflow combining dispersive QuEChERS extraction for rapid sample preparation, liquid chromatography with fluorescence detection (LC-FL) for initial screening, and gas chromatography–tandem mass spectrometry (GC-MS/MS) for confirmation. The aim is to demonstrate a streamlined procedure delivering high sensitivity, low detection limits and robust quantitation across diverse seafood matrices.

Methodology and Instrumentation

Sample Preparation

• Homogenize 15 g tissue; for finfish/shrimp add 5 mL water.
• Spike recovery/QC samples with PAH mix.
• Add DisQuE dispersive salts (6 g MgSO₄, 1.5 g NaOAc) and 15 mL acetonitrile; shake 1 min; centrifuge.
• For LC-FL: dilute supernatant 1:10 or 1:100 in acetonitrile; inject directly.
• For GC-MS/MS: dilute 1 mL extract to 3 mL water, add internal standards; perform tandem SPE (Oasis HLB, then silica) with hexane/DCM, concentrate eluate to 0.25 mL hexane.

Used Instrumentation

• LC-FL: ACQUITY H-Class FLR with large volume flow cell, Waters PAH column (4.6×50 mm, 3 µm) at 35 °C; flow 2.0 mL/min; timed wavelength program; Empower 2 software.
• GC-MS/MS: Waters Quattro Micro GC, Rxi-5Sil column (30 m×0.25 mm×0.25 µm), splitless injection (1 µL), helium at 0.8 mL/min; oven 50 °C to 310 °C at 10 °C/min; EI+ MRM transitions for 16 PAHs; data acquisition via timed MRM.

Main Results and Discussion

LC-FL screening detected 16 PAHs with clear chromatographic resolution; fluorescence sensitivity enabled rapid identification at 10 µg/g spiking. GC-MS/MS confirmation achieved limits of quantitation below 50 ng/g across all PAHs, with linear calibration (r² ≥ 0.995) over 5–100 ng/g. Recoveries for oysters (n=9) averaged above 85% for most analytes, with relative standard deviations under 10%. The combined workflow reduced sample preparation time and solvent usage compared to traditional liquid–liquid extractions.

Benefits and Practical Applications

This protocol offers a cost-effective, high-throughput solution for seafood monitoring laboratories. The QuEChERS approach yields extracts suitable for both LC screening and GC-MS/MS confirmation without extensive solvent exchanges for LC-FL, while a minimal SPE cleanup ensures robust MS performance. Rapid turnaround supports routine QA/QC, regulatory compliance and emergency response after contamination incidents.

Future Trends and Potential Applications

Advancements may include automated QuEChERS platforms, miniaturized SPE cartridges and coupling to high-resolution mass spectrometry for non-targeted PAH profiling. Integration with digital laboratory information management systems (LIMS) and AI-driven data analysis can further streamline reporting and trend monitoring. Adaptation to other food and environmental matrices will broaden application scope.

Conclusion

The optimized dispersive extraction coupled with fluorescence screening and tandem mass-spectrometric confirmation provides a unified, efficient workflow for PAH analysis in seafood. It delivers high sensitivity, reproducibility and regulatory compliance, enabling laboratories to safeguard public health with reduced resource consumption.

Reference

Young MS, Benvenuti ME, Burgess JA, Fountain KJ. Determination of PAH in Seafood: Optimized Sample Preparation Procedures for LC-Fluorescence Screening and GC-MS(MS) Confirmation. Waters Corporation; 2011.