Persistent organic pollutants (POPs) in food

Importance of the Topic

Persistent organic pollutants (POPs) are a class of synthetic chemicals characterized by their environmental persistence, bioaccumulation in fatty tissues, and toxicity to wildlife and humans. In food matrices such as fish, honey, dairy products, and human breast milk, trace levels of POPs—including dioxins, polychlorinated biphenyls (PCBs), chlorinated paraffins, brominated flame retardants, perfluorinated compounds, and pesticide residues—pose significant risks to public health and require reliable monitoring. Regulatory frameworks (e.g. Stockholm Convention, European Commission limits) mandate sensitive, selective, and high-throughput analytical methods for routine surveillance and risk assessment.

Study Objectives and Overview

This compendium of application studies aimed to develop, validate, and compare advanced sample preparation and chromatographic–mass spectrometric workflows for quantifying a broad spectrum of POPs in various food and environmental samples. Key goals included reducing solvent consumption, increasing throughput, achieving low detection limits (sub-ppt to low ppb), and ensuring unambiguous confirmation of target analytes in complex matrices.

Methodology and Instrumentation

Sample Preparation and Cleanup

• Accelerated Solvent Extraction (ASE) with inline cleanup for fatty tissues (fish, honey).
• Solid-phase extraction and protein precipitation for aqueous and biological matrices.
• Column-switching and trapping strategies to improve chromatographic resolution.

Chromatographic Separation and Detection

• Gas Chromatography coupled to Triple Quadrupole MS/MS for targeted quantitation of PCBs, organochlorine pesticides, PBDEs, and short-chain chlorinated paraffins.
• GC–ICP-MS for compound-specific analysis of brominated flame retardants, leveraging elemental bromine detection.
• High-resolution GC–HRMS with magnetic sector and Orbitrap platforms for dioxins/furans, unknown screening, and confirmation workflows.
• Liquid Chromatography–MS/MS for selective reaction monitoring of perfluorinated compounds and nitrofuran metabolites in milk and honey.

Main Results and Discussion

Across multiple case studies:

• ASE strategies cut sample preparation time and solvent use by over 50% compared with classical Soxhlet or sonication.
• Triple quadrupole GC-MS/MS methods attained limits of quantitation down to low ppt while delivering robust confirmation criteria (ion ratios, SRM transitions).
• Orbitrap-based HRAM GC-MS achieved exact-mass measurements for complex unknown screening, resolving analyte peaks from matrix interferences.
• GC–ICP-MS minimized thermal decomposition artifacts, enabling full congeners profiling of higher-brominated flame retardants.
• LC-MS/MS assays for PFCs and nitrofuran markers demonstrated excellent linearity, precision (<10% RSD), and recovery (>80%) in challenging food matrices.

Benefits and Practical Applications

The described workflows support:

• Routine compliance testing in food safety laboratories and regulatory agencies.
• Environmental monitoring of POPs in water, soil, and biota.
• Research on bioaccumulation, human exposure, and ecotoxicology of emerging contaminants.
• High-throughput screening in quality control (QA/QC) for agricultural and industrial food products.

Future Trends and Opportunities

Emerging directions include:

• Integrated unknown and targeted screening platforms combining HRAM and triple quadrupole capabilities for broader analyte coverage.
• Automated, miniaturized sample preparation modules to further reduce solvent and consumable usage.
• Advanced data processing with machine learning to flag suspect peaks and predict degradation products.
• Development of multiplexed assays for simultaneous monitoring of legacy and novel POPs in diverse matrices.

Conclusion

The collective studies demonstrate that modern extraction techniques and state-of-the-art MS technologies deliver sensitive, selective, and high-throughput solutions for POP analysis in food and environmental samples. These methods align with regulatory requirements and support large sample loads while minimizing solvent consumption and labor intensity.

Used Instrumentation

• Thermo Scientific Dionex ASE 350 Accelerated Solvent Extractor
• Thermo Scientific TRACE 1310 Gas Chromatograph with Instant Connect injector
• Thermo Scientific TSQ 8000 Evo and TSQ Quantis Triple Quadrupole GC-MS/MS
• Thermo Scientific Exactive GC Orbitrap and Q Exactive Plus Hybrid Quadrupole-Orbitrap MS
• Thermo Scientific DFS Magnetic Sector GC-HRMS
• Thermo Scientific iCAP Q and RQ ICP-MS systems
• Thermo Scientific TriPlus RSH Autosampler
• Various GC columns (TraceGOLD TG-5SilMS, TR-Dioxin, Accucore RP-MS) and LC columns (Hypersil GOLD PFP)

References

Thermo Fisher Scientific Inc. Application Note 10509: "Persistent Organic Pollutants (POPs) in Food". 2017.