Rapid qualitative and quantitative analysis of residual solvents in food packaging by static headspace coupled to GC-FID/MS

Importance of the topic

Food packaging materials can release residual solvents derived from polymers, inks and coatings into food, posing potential health and sensory risks. Regulatory frameworks such as the European Standard EN 13628-1 and FDA limits control these contaminants to ensure consumer safety. Robust analytical methods are essential for accurate determination of volatile and semi‐volatile solvent residues in solid packaging matrices without extensive sample preparation.

Objectives and overview of the study

This application note demonstrates a fully automated workflow for both qualitative and quantitative analysis of residual solvents in flexible food packaging, following EN 13628-1:2002. Using the Thermo Scientific™ TriPlus™ 500 headspace autosampler coupled to a dual‐detector GC‐FID/MS system, the study aims to:

• Evaluate method linearity and precision by multiple headspace extraction (MHE).
• Identify and quantify trace solvents in real packaging samples.
• Showcase extended automation from sampling through data reporting.

Methodology and Instrumentation

Samples of cling film, wraps and trays were cut to 40 cm2 pieces and placed in 10 mL headspace vials. Two solvent standard mixtures covering common packaging impurities were used for calibration. Static headspace with MHE (four extraction cycles; incubation at 120 °C for 40 min) enabled absolute quantitation without matrix calibration. Key instrumental settings:

• Autosampler: TriPlus 500 HS with medium vial shaking, pressure equilibration, 1 mL loop.
• Gas chromatograph: TRACE 1310 GC, split injection (20:1), He carrier at 110 kPa.
• Column: TraceGOLD TG-1MS (30 m × 0.32 mm, 3.0 µm).
• Detectors: Microfluidics splitter to FID (air/H2 flows 350/35 mL/min) and ISQ 7000 single quadrupole MS (EI, 70 eV, full‐scan m/z 25–350).
• Data system: Chromeleon 7.2 CDS controlling acquisition, processing and reporting.

Main results and discussion

• Calibration linearity was excellent (R2 ≥ 0.997 for MS, R2 = 1.000 for FID) across 23 target solvents, meeting EN 13628-1 requirements.
• Residual solvents were detected in three of six packaging samples: salad wrap contained ethanol (0.97 mg/m2) and acetone (1.9 mg/m2). Sliced salami lid and tray released ethyl acetate at 0.76 and 29 mg/m2, respectively. Other materials (pizza film, cookie and bread wraps) were free of detectable solvents.
• Dual detection improved confidence: FID provided quantitation while MS full‐scan spectra enabled putative identification of unknowns such as acetaldehyde (SI 953) and other library‐matched compounds.
• Fast GC ramp (50 °C to 250 °C in <7 min) with high chromatographic resolution (Rs ≥ 1.0) increased sample throughput. Overlapping MHE cycles and 240‐vial capacity allowed unattended 24-h operation.

Benefits and practical applications

• Matrix‐independent quantitation via MHE eliminates polymer dissolution and injector contamination.
• Automated sequence from sample intake to report reduces human error and boosts lab productivity.
• Dual FID/MS detection ensures accurate quantification and reliable compound confirmation in a single run.
• High‐throughput capability suits routine QA/QC testing in food packaging manufacturing and compliance laboratories.

Future trends and applications

• Integration of two‐dimensional GC or high‐resolution MS to resolve complex mixtures and trace impurities.
• Miniaturized or ambient desorption techniques for faster screening of novel packaging materials.
• Machine‐learning enhanced spectral libraries for improved unknown identification and automated reporting.
• Expanded headspace methods to monitor non‐volatile migrants and reaction products under real‐world storage conditions.

Conclusion

The TriPlus 500 HS autosampler coupled to TRACE 1310 GC‐FID/MS demonstrated full compliance with EN 13628-1:2002 for residual solvent determination in food packaging. The method delivered outstanding linearity, sensitivity and throughput while minimizing sample preparation and maintenance. Dual detection and automated data workflows enhance confidence in results and enable efficient regulatory compliance testing.

Reference

1. EN 13628-1:2002 Packaging – Flexible Packaging Material – Determination of residual solvents by static headspace gas chromatography – Part 1: Absolute methods.
2. Regulation (EC) No 1935/2004 on materials and articles intended to come into contact with food.
3. 21 CFR 170.3, 174–179: Direct and indirect food additives – solvent migration limits.
4. Kolb B. and Ettre L., Static Headspace‐Gas Chromatography: Theory and Practice, 2nd Ed., Wiley, 2006.
5. Thermo Fisher Scientific. Chromeleon CDS Enterprise – Compliance, Connectivity, Confidence, BR72617-EN0718S.
6. Kosowska M., Majcher M.A., Fortuna T., Volatile compounds in meat and meat products, Food Sci. Technol. (Campinas) 37(1):1–7, 2017.
7. ILSI Europe, Printing inks for food packaging composition and properties of printing inks, Dec. 2011.