Perfluoroalkyl Substances (PFAS) Testing Guide

Significance of Topic

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals applied in food packaging and other consumer products. Their exceptional stability and resistance to degradation lead to widespread environmental persistence, bioaccumulation, and potential chronic health effects. Migration of PFAS from packaging into consumable goods and entry into the food chain via contaminated water and feed underscores the need for robust analytical methods.

Objectives and Study Overview

This guide summarizes two complementary analytical approaches:

• Quantitative determination of 23 PFAS in dairy products, eggs, and fish using a modified QuEChERS extraction, optional solid-phase extraction cleanup, and triple-quadrupole LC-MS/MS.
• Identification and quantification of 17 PFAS in food contact materials employing a Scheduled MRMHR workflow on a high-resolution QTOF mass spectrometer.

Methodology and Instrumentation Used

Workflow 1 (Food Matrices):

• Sample Preparation: Homogenization, spiking with internal standards, acetonitrile–water extraction via QuEChERS kit, optional weak anion-exchange SPE cleanup (Strata-X-AW).
• Chromatography & Detection: Agilent 1290 UHPLC with Phenomenex Luna Omega PS C18 column; Agilent 6460 QQQ in negative electrospray mode with ammonium acetate/acetonitrile gradient.

Workflow 2 (Packaging Materials):

• Extraction: Solvent extraction of cut packaging pieces following China National Standard GB 31604.35-2016.
• Chromatography: SCIEX ExionLC AD with Phenomenex Kinetex C18 column and gradient of methanol/ammonium acetate.
• Detection: SCIEX X500R QTOF using Scheduled MRMHR acquisition for high-resolution MS/MS transitions.

Main Results and Discussion

• Triple-quad LC-MS/MS achieved linear calibration from 0.05 to 1000 ppb, 0.05 ppb LOQ, and recoveries of 80–120 % for 23 PFAS spiked at 1 ng/g across diverse food matrices. SPE cleanup enabled quantification at 0.1 ng/g in eggs.
• High-resolution QTOF MRMHR delivered enhanced selectivity and signal-to-noise for 17 PFAS, with correlation coefficients > 0.99 and accurate ion-ratio confirmation.
• Screening of eight packaging samples detected eight PFAS compounds; PFOA levels in non-stick pan coatings and meal boxes surpassed the 1 ng/g regulatory limit.

Benefits and Practical Applications

• Sub-ppb quantification workflows for complex food matrices support regulatory monitoring and food safety assessment.
• MRMHR on QTOF integrates quantitative and qualitative confirmation in a single high-resolution dataset, reducing false positives.
• Techniques are adaptable for industry and governmental labs to enforce PFAS limits in foods and packaging materials.

Future Trends and Potential Applications

The PFAS analytical landscape will expand to:

• Non-target and suspect screening of thousands of PFAS and their transformation products using high-resolution accurate-mass instruments.
• Prioritization of PFAS based on toxicity profiles informed by structure-activity relationships.
• Multi-laboratory validation and harmonization of food and packaging methods for global regulatory alignment.
• Automation of sample preparation workflows to increase throughput and minimize matrix interferences.

Conclusion

Combining advanced extraction techniques with modern LC-MS/MS and QTOF platforms enables reliable detection of PFAS at trace levels in both food and packaging matrices. Ongoing method development and high-resolution screening are essential to address emerging PFAS challenges and safeguard public health.

Reference

1. FDA Analytical Results of Testing Food for PFAS from Environmental Contamination, 2020.
2. EPA Basic Information about PFAS, 2018.
3. ATSDR Toxicological Profile for Perfluoroalkyls, 2020.
4. FDA Removal of PFAS Approvals in Food Packaging, 2016.
5. EPA Unregulated Contaminant Monitoring Rule 5 (UCMR5), 2019.
6. DOD PFAS Assessments at Military Installations, 2019.
7. FDA Guidance on PFAS in Food Supply Chain, 2019.
8. Pierri & Krepich, Phenomenex Technical Note TN-0124: PFAS in Food by QuEChERS SPE LC-MS/MS, 2018.