Rapid Automated Screening of Extractable Compounds in Materials for Food Packaging, Medical or Technical Purposes

Significance of the Topic

Monitoring extractable and leachable compounds is essential to ensure the safety and integrity of food, pharmaceutical, medical, and technical products. Identifying potential contaminants released from packaging and device materials helps prevent product spoilage, health hazards, and analytical interference.

Objectives and Overview of the Study

This study presents two automated screening approaches for characterizing extractable compounds in materials used for food packaging, medical devices, and technical applications. Method 1 employs automated liquid extraction (LE) using the GERSTEL MultiPurpose Sampler (MPS). Method 2 utilizes direct thermal desorption (TD) in the GERSTEL Thermal Desorption Unit (TDU). The goal is to compare qualitative profiles, sensitivity, and throughput to support rapid material evaluation.

Methodology and Instrumentation Used

• Liquid Extraction (LE): Sample pieces are rinsed with isopropanol and placed in 1.5 mL vials containing 500 µL ethyl acetate spiked with d10-phenanthrene. Extraction is performed in a heated agitator at 45 °C for 4 h, 750 rpm, followed by 1.5 µL injection via a cooled PTV inlet (CIS) into GC/MS.
• Thermal Desorption (TD): Dried sample fragments are loaded into TDU tubes and desorbed between 100 °C and 200 °C at up to 250 °C/min. Analytes are cryo-focused in the CIS at –120 °C and transferred to the GC column.

Instrumentation Used

• Agilent 7890 GC with 5975 MS detector (EI, full scan).
• GERSTEL MultiPurpose Sampler (MPS) with heated agitator.
• GERSTEL Thermal Desorption Unit (TDU) and Cooled Injection System (CIS).
• 30 m Rxi-5ms column, 0.25 mm i.d., 0.25 µm film, He carrier at 1.0 mL/min.

Main Results and Discussion

• Blank runs for both LE and TD showed minimal background interference, confirming system cleanliness.
• LE proved highly rugged: extracts remained stable even after a 10 h delay on the autosampler tray.
• TD exhibited 10–60× greater sensitivity for volatile and semi-volatile analytes, while LE extracted high-boiling compounds more efficiently.
• By adjusting TD split ratio and desorption temperature, chromatographic patterns matched those of LE, demonstrating method interchangeability.
• Screening of ~70 commercial samples revealed common extractables—monomers, oligomers, plasticizers (phthalates, citrates), UV stabilizers, and hydrocarbons.
• Hazardous substances such as diisocyanates, bisphenol A, and long-chain hydrocarbons were detected in some food packaging films and closures.
• Medical and laboratory-grade polymers showed very low extractable profiles, proving feasibility of producing clean materials cost-effectively.

Benefits and Practical Applications of the Method

• Fully automated workflows improve reproducibility and throughput, enabling high-capacity screening.
• Rapid qualitative profiling aids selection of packaging and device materials with low emission potential.
• Use of an internal standard facilitates quantitative comparison across instruments and time points.
• Parallel extraction and analysis shorten total cycle time and increase laboratory efficiency.

Future Trends and Opportunities for Use

Regulatory focus on mineral oil hydrocarbons (MOSH/MOAH) in recycled fibers highlights the need for expanded screening. Integration with mVAP solvent exchange will allow coupling to liquid chromatography. Emerging materials, multilayer constructions, and complex food matrices present new challenges and opportunities for automated extractables profiling.

Conclusion

The two automated methods provide complementary, robust tools for qualitative extractables screening. LE and TD can be tailored to cover a broad range of analytes and emission potentials, guiding the selection and quality control of packaging and medical materials.

References

1. CHMP/CVMP Guideline on Plastic Immediate Packaging Materials. European Medicines Evaluation Agency, 2005.
2. Center for Drug Evaluation and Research. Guidance for Industry: Container Closure Systems for Packaging Human Drugs and Biologics. FDA, 1999.
3. US Food and Drug Administration. 21 CFR Part 177 Indirect Food Additives: Polymers, 2011.
4. Pfannkoch E, Whitecavage J. Stir Bar Sorptive Extraction from Food Simulating Solvents: Preliminary Studies. GERSTEL AppNote 3/2002.
5. Wikipedia contributors. Mineral oil hydrocarbons. www.wikipedia.org.
6. Lorenzini R et al. Saturated and Aromatic Mineral Oil Hydrocarbons from Paperboard Foodpackaging: Estimation of Long-term Migration. Food Additives & Contaminants A 27(2010):1765–1774.