Determination of 30 PFAS in Fish Oil, Coffee Powder, and Protein Powder

Importance of the topic

This application addresses the growing concern over per- and polyfluoroalkyl substances (PFAS) residues in food products. PFAS are persistent environmental contaminants linked to adverse health effects. Regulatory bodies such as the European Commission and AOAC International have set stringent limits for PFAS in various food categories. Reliable analytical methods are essential for monitoring PFAS in complex matrices like fish oil, coffee powder, and protein powder to ensure food safety and regulatory compliance.

Objectives and study overview

The main goal of this study was to develop and validate a streamlined multiresidue method for quantifying 30 PFAS compounds in fish oil, coffee powder, and plant-based protein powder. The method integrates QuEChERS extraction, enhanced matrix removal (EMR) mixed-mode cleanup using Agilent Captiva EMR PFAS Food II cartridges, and liquid chromatography coupled with triple quadrupole mass spectrometry (LC/TQ). Validation followed AOAC SMPR 2023.003 guidelines, evaluating sensitivity, accuracy, precision, and method limits of quantitation (LOQs).

Methodology

• Sample preparation: 1 g of coffee or protein powder, or 2 g of fish oil, spiked with native PFAS standards and isotopically labeled internal standards (ISTDs).
• Extraction: Addition of water, acetonitrile with 1% acetic acid, QuEChERS EN salts, ceramic homogenizers; shaking on Geno/Grinder and centrifugation.
• EMR cleanup: Supernatant diluted with 10% water, loaded onto Captiva EMR PFAS Food II cartridges (3.5 mL), gravity elution followed by 10 psi air drying.
• Direct injection: Eluate injected directly in feed injection mode using Agilent 1260 Infinity II hybrid multisampler, eliminating drying and reconstitution steps.
• LC/TQ detection: Agilent 1290 Infinity II LC coupled to 6495D triple quadrupole MS with Jet Stream iFunnel ESI in negative mode; ZORBAX RRHD Eclipse Plus C18 column; gradient elution; scheduled multiple reaction monitoring (MRM) transitions from the PFAS database.

Used instrumentation

• Agilent 1290 Infinity II LC system (binary pump, hybrid multisampler, column compartment).
• Agilent 6495D triple quadrupole mass spectrometer with Jet Stream iFunnel ESI source.
• Agilent InfinityLab PFC-free HPLC conversion kit, ZORBAX RRHD Eclipse Plus C18 analytical column, guard column.
• Captiva EMR PFAS Food II cartridges, Agilent Bond Elut QuEChERS EN extraction kit.

Key results and discussion

Matrix blanks revealed trace PFAS background in all three matrices, with protein powder showing the highest levels. Method LOQs met or surpassed AOAC SMPR requirements: core PFAS targets (PFOA, PFOS, PFNA, PFHxS) achieved LOQs ≤0.3 µg/kg; PFBA and PFPeA ≤1 µg/kg; other PFAS ≤5 µg/kg. Thirty PFAS analytes demonstrated acceptable recoveries (80–120%) and repeatability (RSD < 20%) at the LOQ level, and excellent performance (recoveries 80–120%, RSD < 10%) at mid- and high-level QC spikes. Chromatographic optimization provided baseline separation of isomeric interferences (e.g., PFOS/cholic acids) and consistent peak shapes even with a 10 µL injection in high organic content.

Benefits and practical applications

• Streamlined workflow reducing sample preparation time by up to 50% by eliminating evaporation and reconstitution.
• High sensitivity and robustness across diverse food matrices to support routine PFAS monitoring in QA/QC and regulatory laboratories.
• Cost-effective consumables and minimal solvent use.
• Compliance with EU and AOAC SMPR guidelines, facilitating adoption in global food safety programs.

Future trends and potential applications

Advances may include automation of EMR cleanup using online platforms, expansion to additional food matrices, and coupling with high-resolution MS for non-targeted PFAS screening. Machine learning algorithms could predict cleanup efficiency and retention behavior. Growing regulatory requirements will drive further refinement of multiresidue PFAS methods and adoption of harmonized international standards.

Conclusion

A robust, validated method has been demonstrated for 30 PFAS in fish oil, coffee powder, and protein powder using QuEChERS extraction, EMR passthrough cleanup, and LC/TQ analysis. The approach meets stringent AOAC SMPR 2023.003 and EU requirements with excellent sensitivity, accuracy, and precision. Its efficiency and reliability support high-throughput PFAS monitoring in food safety laboratories worldwide.

References

1. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for contaminants in food.
2. AOAC International, SMPR 2023.003: Performance Requirements for PFAS in Food.
3. Zhao L., Giardina M., Parry E. Determination of 30 PFAS in Infant Formula, Milk, and Eggs; Agilent Technologies Application Note 5994-7366EN, 2024.
4. Zhao L., Giardina M., Parry E. Determination of 30 PFAS in Baby Food; Application Note 5994-7367EN, 2024.
5. Zhao L., Giardina M., Parry E. Determination of 30 PFAS in Beef, Tuna, and Shrimp; Application Note 5994-7368EN, 2024.
6. Zhao L., Giardina M. Determination of 30 PFAS in Fruits, Vegetables, and Juices; Application Note 5994-7369EN, 2024.
7. Zhao L., Giardina M., Parry E. Determination of 30 PFAS in Bovine Kidney; Application Note 5994-7370EN, 2024.
8. Zhao L., Giardina M., Parry E. Determination of 30 PFAS in Dry Soybeans; Application Note 5994-7371EN, 2024.