Food Packaging Volatiles by Purge & Trap GCMS - Rtx®-5MS

Significance of the Topic

Volatile organic compounds (VOCs) released from food packaging materials can affect food safety, quality and consumer health. Sensitive and reproducible analytical methods are essential for identifying and quantifying these trace-level volatiles to ensure compliance with regulatory limits and to support product development and quality control in the food industry.

Objectives and Study Overview

This application note demonstrates a purge & trap gas chromatography–mass spectrometry (GC-MS) technique for profiling VOCs from food packaging components. The study aimed to:

• Isolate and concentrate trace VOCs emitted from a plastic overwrap and bowl lid.
• Separate and identify key volatiles using an Rtx®-5MS column.
• Establish method parameters that deliver robust sensitivity and reproducibility.

Methodology and Instrumentation

Sample preparation and instrumental conditions were optimized as follows:

• Purge & Trap System: Tekmar LSC-3100 with Vocarb 3000 (type K) trap.
• Purge Conditions: 10 min at 40 mL/min helium flow and 60 °C.
• Dry Purge: 3 min at 40 mL/min to remove moisture.
• Thermal Desorption: preheat 220 °C; desorb at 245 °C for 2 min with 40 mL/min carrier gas.
• GC Column: Rtx®-5MS, 30 m × 0.25 mm ID, 1 µm film thickness.
• GC Conditions: 50 °C initial, ramp to 92 °C at 3 °C/min, then to 220 °C at 20 °C/min (1 min hold).
• Carrier Gas: Helium at 1 mL/min (linear velocity 36 cm/s); injector at 250 °C with 1:20 split.
• MS Detection: Agilent 5973 MSD, EI ionization at 70 eV, scan range 35–260 amu, detector at 280 °C.

Key Findings and Discussion

Analysis of the overwrap and bowl lid identified eight primary VOCs: tetrahydrofuran, ethylbenzene, 4-heptanone, styrene, benzaldehyde, nonanal, decanal, and cinnamaldehyde. Chromatograms showed distinct separation with baseline resolution. The purge & trap technique provided sufficient enrichment to detect compounds down to low microgram per liter levels. Reproducibility was demonstrated by consistent retention times and peak areas across replicate runs.

Benefits and Practical Applications

• High sensitivity for trace-level detection of packaging migrants.
• Effective moisture removal minimizes compound loss and interference.
• Wide dynamic range suitable for QC and compliance testing.
• Method versatility allows screening of various polymer types and additives.

Future Trends and Potential Applications

Advances in trap materials and automated sampling can further lower detection limits and improve throughput. Coupling with high-resolution mass spectrometry may enable accurate mass measurement for unknown VOC identification. Integration into routine QA/QC workflows supports rapid screening of emerging packaging materials and novel biopolymers.

Conclusion

The purge & trap GC-MS method described offers a robust analytical platform for characterizing volatile migrants from food packaging. Its sensitivity, reproducibility and adaptability make it a valuable tool for ensuring packaging safety and guiding material selection.

Reference

Restek Corporation Application Note: Food Packaging Volatiles by Purge & Trap GC-MS, Agilent 6890 GC and 5973 MSD, Tekmar LSC-3100 purge & trap system, Rtx®-5MS column.