Determination of Persistent Organic Pollutants in Fish Tissues by Accelerated Solvent Extraction and GC-MS/MS

Significance of the Topic

Persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) are highly stable, lipophilic compounds that bioaccumulate in fish tissues and magnify up the food chain. Their resistance to degradation and known toxicity make sensitive, reliable analytical methods essential for food safety and environmental monitoring.

Objectives and Study Overview

This study develops and validates a rapid accelerated solvent extraction (ASE) combined with gas chromatography–tandem mass spectrometry (GC-MS/MS) approach for simultaneous determination of 29 POPs in bluefin tuna (Thunnus thynnus) from four FAO catch areas. Concentration ranges targeted were 1–100 ng/g for PCBs, 0.5–10 ng/g for PBDEs and 5–1 000 ng/g for OCPs.

Methodology

• Sample preparation: Ninety-nine samples from three anatomical zones per fish were homogenized with diatomaceous earth and sodium sulfate; 3 g aliquots spiked with internal standards.
• Extraction: Thermo Scientific ASE 350 with in-cell silica gel clean-up; solvent n-hexane/acetone (4:1) at 80 °C, 1 500 psi, three 10 min static cycles; rinse 90 %, purge 90 s.
• Concentration: Extracts dried over sodium sulfate, evaporated with Genevac Rocket Evaporator, reconstituted in 200 µL isooctane.
• Analysis: TRACE 1310 GC with Rt-5MS column coupled to TSQ 8000 GC-MS/MS; EI source, SRM transitions optimized for quantifier and qualifier ions under collision energies of 10–30 eV.

Instrumentation

• Thermo Scientific Dionex ASE 350 Accelerated Solvent Extractor
• Genevac Rocket Evaporator
• Thermo Scientific TRACE 1310 GC with Split/Splitless injector and Rt-5MS capillary column
• Thermo Scientific TSQ 8000 Triple Quadrupole GC-MS/MS
• Radwag analytical balance

Results and Discussion

The method exhibited excellent linearity (r2 ≥ 0.99), limits of detection from 0.01–1.48 ng/g and quantification from 0.03–4.44 ng/g. Recoveries ranged 75–119 % with RSDs ≤ 14 %. Application revealed higher PCB and PBDE concentrations in Mediterranean (FAO area 37) samples (up to 69.7 ng/g for PCBs; 6.3 ng/g for PBDEs) versus other regions. Key OCPs detected included endosulfan sulfate (prevalence 65–89 %, ~7 ng/g) and endrin (up to 39 ng/g).

Applications and Practical Benefits

This one-step ASE approach integrates extraction and clean-up, halving solvent consumption and sample preparation time compared to Soxhlet/sonication with GPC/SPE. MS/MS detection ensures high selectivity and sensitivity for trace-level monitoring in routine QA/QC, research and regulatory laboratories.

Future Trends and Potential Uses

• Extension to additional matrices (meat, dairy) and emerging flame retardants
• Automation of concentration and transfer steps for higher throughput
• Integration with high-resolution MS for non-target screening
• Miniaturized ASE systems for on-site environmental analysis

Conclusion

The developed ASE-GC-MS/MS method provides a robust, efficient multi-residue workflow for POP analysis in fish tissues, delivering reliable quantification with reduced solvent use and processing time, thereby supporting regulatory compliance and environmental safety efforts.

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