Automated Sample Preparation Using Andrew+™ Pipetting Robot Configured with Extraction+ for Solid Phase Extraction (SPE) of Per- and Polyfluoroalkyl Substances (PFAS) in Food Packaging Material Analysis

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) serve as grease-proofing agents in food packaging and can migrate into food, raising health concerns and prompting regulatory restrictions. Reliable monitoring of PFAS in packaging is essential for consumer safety and environmental protection.

Objectives and Study Overview

This work presents an end-to-end workflow for quantifying 27 PFAS in food packaging materials. The study focuses on automating solid phase extraction (SPE) using an Andrew+ pipetting robot configured with the Extraction+ device, coupled to LC–MS/MS on a Xevo TQ-Absolute mass spectrometer.

Methodology

Sample Preparation

• Cut 1 dm2 of packaging into 1 cm2 pieces.
• Spike with isotope-labeled internal standards; incubate 1 h.
• Extract with 2% ammonium hydroxide in methanol, sonicate at 60 °C for 60 min.
• Dilute extract with 1% formic acid solution.

SPE Clean-up

• Use Oasis WAX cartridges tailored for PFAS retention.
• Automate conditioning, loading, washing, and elution steps via Andrew+ and Extraction+ under OneLab software, with programmable vacuum control.

LC–MS/MS Analysis

• LC: ACQUITY I-Class UPLC with PFAS-optimized isolator pre-column; mobile phases aqueous 2 mM ammonium acetate and ACN/water (98:2) with 2 mM ammonium acetate; flow 0.4 mL/min.
• MS: Xevo TQ-Absolute, ESI negative mode, capillary 1 kV, desolvation 550 °C.
• Data processed using MassLynx and TargetLynx v4.2.

Instrumental Setup

• Andrew+ Pipetting Robot with Extraction+ connected device.
• Oasis WAX SPE cartridges for PFAS.
• Waters ACQUITY UPLC I-Class with PFAS isolator column.
• Xevo TQ-Absolute triple quadrupole mass spectrometer.
• MassLynx and TargetLynx software.

Results and Discussion

Calibration and Linearity

• Automated preparation of an internal standard series (1–1000 pg/mL) for 27 PFAS yielded r2 > 0.995, matching manual protocols.

Recovery and Matrix Effects

• Spiking 14 isotope-labeled PFAS into food-wrapping paper showed recoveries of 85–122% and matrix effects between 78–127%. Automated SPE matched manual performance.
• SPE clean-up significantly improved signal sensitivity by removing matrix interferences.

Analysis of Market Samples

• Five common packaging types (paper, boxes, bag) were tested; all contained native PFAS; up to 12 compounds detected in single samples, including PFOA in all materials.

Benefits and Practical Applications

• Automation reduces manual pipetting errors and frees analyst time.
• Consistent SPE performance enhances reproducibility across batches.
• Low detection limits down to 1 pg/dm2 support regulatory compliance.

Future Trends and Potential Applications

Emerging needs include expanding the PFAS target list, integrating high-throughput robotics for diverse packaging types, and coupling with next-generation high-resolution MS for non-target screening. Cloud-native software will facilitate remote protocol sharing and method transfers across laboratories.

Conclusion

The automated SPE workflow using Andrew+ and Extraction+, combined with sensitive LC–MS/MS, provides a robust, reproducible, and high-throughput solution for PFAS analysis in food packaging materials, aiding in exposure assessment and regulatory monitoring.

Reference

1. Sapozhnikova, Y.; Taylor, R.B.; Bedi, M.; Ng, C. Assessing Per- and Polyfluoroalkyl Substances in Globally Sourced Food Packaging. Chemosphere 2023, 337, 139381.
2. Schwartz-Narbonne, H.; Xia, C.; Shalin, A.; Whitehead, H.D.; Yang, D.; Peaslee, G.F.; Wang, Z.; Wu, Y.; Peng, H.; Blum, A.; Venier, M.; Diamond, M. Per- and Polyfluoroalkyl Substances in Canadian Fast Food Packaging. Environ. Sci. Technol. Lett. 2023.
3. LBK nr 1033 af 05/07/2023, Ministeriet for Fødevarer, Landbrug og Fiskeri. Retsinformation. 2023.