Quantifying Primary Aromatic Amines in Polyamide Kitchenware Using the ACQUITY UPLC I-Class System and Xevo TQ-S micro

Significance of the Topic

Primary aromatic amines (PAAs) are small, basic organic compounds used in the manufacture of azo pigments and various polymeric materials. Certain PAAs have been identified as human carcinogens, raising concerns about their migration from food-contact materials into food. Regulatory bodies in the EU have established stringent migration limits under Regulation 10/2011 and its update EU 2020/1245, necessitating reliable analytical methods capable of detecting trace levels of up to 23 target PAAs in kitchenware products.

Study Aims and Overview

This application note describes the development and validation of a single LC-MS/MS assay for simultaneous quantification of 23 common PAAs in polyamide kitchenware migration extracts. The workflow emphasizes straightforward sample preparation, elimination of ion-pair reagents, and attainment of sub-ppb detection limits to comply with EU 2020/1245 specifications. The study examines method performance, linearity, detection limits, matrix effects, and application to real-world kitchenware samples.

Methodology and Instrumentation

Sample Preparation:

• Migration test using 3% (w/v) acetic acid simulant per EU 10/2011 guidelines.
• pH adjustment of 1 mL extract by adding 10 µL of 25% NH4OH to improve chromatographic retention and peak shape of basic PAAs.

Chromatography and Detection:

• System: ACQUITY UPLC I-Class with HSS T3 column (2.1×100 mm, 1.8 µm) at 45 °C.
• Mobile phases: water (A) and methanol (B); gradient from 5% B to 100% B in 10 min, 15 min total run.
• Injection volume: 20 µL; flow rate: 0.4 mL/min.
• Post-column addition of 0.1% formic acid (via 2% formic acid infused at 20 µL/min) to enhance ESI+ sensitivity.

Mass Spectrometry:

• Xevo TQ-S micro triple quadrupole in ESI positive mode.
• MRM acquisition with two transitions per compound, dwell times optimized automatically.
• Desolvation temperature: 600 °C; capillary voltage: 2 kV; desolvation gas: 1200 L/h.

Main Results and Discussion

Linearity and Sensitivity:

• Calibration range: 0.78–100 ng/mL (1/X weighted linear regression).
• Excellent linearity for all 23 PAAs with residuals within acceptable limits.
• Estimated limits of quantitation (LOQ) between 20 pg/mL and 300 pg/mL, satisfying sub-ppb requirements.

Matrix Effects and Accuracy:

• Spike recoveries in food simulant ranged from 90% to 107%, indicating negligible ion suppression without internal standards.

Application to Kitchenware Samples:

• Nine polyamide utensils tested; only aniline (0.4–1.1 ppb) and 4,4′-diaminodiphenylmethane (0.04–0.11 ppb) detected.
• All findings were below individual and total specific migration limits under EU 2020/1245.

Benefits and Practical Applications

• Unified LC-MS/MS method for 23 PAAs reduces analysis time and resource use.
• Avoidance of ion-pair reagents preserves electrospray sensitivity and simplifies preparation.
• Post-column formic acid addition significantly boosts signal intensity at trace concentrations.
• Suitable for routine QA/QC and regulatory compliance testing of food-contact materials.

Future Trends and Potential Applications

Advances in microflow UPLC and high-sensitivity MS detectors may further lower detection limits and reduce solvent consumption. Integration of automated sample preparation and online dilution could enhance throughput. Growing demand for multi-residue workflows may drive expansion of this method to include other migrants such as bisphenols or nitrosamines in diverse packaging matrices.

Conclusion

The presented LC-MS/MS protocol offers a robust, high-throughput solution for quantifying 23 PAAs in polyamide kitchenware at sub-ppb levels. Key innovations—pH neutralization over ion-pairing and post-column acidification—deliver excellent chromatographic performance and sensitivity. Real-world application confirms compliance with EU 2020/1245 migration limits, supporting its adoption for regulatory and industrial quality control.

References

• Commission Regulation (EU) No 10/2011 of 14 January 2011 on plastic materials and articles intended to come into contact with food.
• Commission Delegated Regulation (EU) 2020/1245 amending Regulation 10/2011 concerning primary aromatic amines.
• Regulation (EC) No 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).
• LB-NA-24815-EN-N. Technical Guidelines on Testing the Migration of Primary Aromatic Amines from Polyamide Kitchenware and of Formaldehyde from Melamine Kitchenware.