Determination of the Migration of Phthalate and Polycyclic Aromatic Hydrocarbon from Food Contact Plastic Bags by GC/MS

Significance of the Topic

Plastic bags are among the most common food packaging materials due to their affordability and adaptability. However, additives such as phthalates and polycyclic aromatic hydrocarbons (PAHs) can migrate into food under heat, storage time and solvent contact, posing potential risks to consumer health and the environment.

Objectives and Overview

This work aims to establish and validate a gas chromatography–mass spectrometry (GC/MS) method for simultaneous determination of 16 phthalate esters (PAEs) and 16 PAHs migrating from polyethylene food-contact bags. The approach follows relevant Chinese national standards, employs five food simulants, and evaluates migration under varying temperatures (20 °C, 40 °C, 70 °C) and times (0.5, 2, 6 hours).

Methodology and Instrumentation

Sample Preparation and Extraction:

• Polyethylene bags cut into 6 cm2 pieces and immersed in 10 mL of each food simulant: 4% acetic acid, 10% ethanol, 20% and 50% ethanol, and isooctane.
• Migration performed at three temperatures for three time points in sealed glass vials.
• For all simulants except isooctane, 2 mL toluene added, mechanically shaken and centrifuged; toluene layer used directly for GC/MS.

Chromatographic and Mass Spectrometric Conditions:

• Instrument: PerkinElmer Clarus® 680 SQ 8 GC/MS with electron ionization source.
• Column: Elite 5MS, 30 m × 0.25 mm × 0.25 µm.
• Injector: splitless at 280 °C, injection volume 1 µL, helium carrier at 1 mL/min.
• Oven temperature program: 50 °C (1 min), ramp to 220 °C, hold, then to 250 °C and 290 °C with defined holds.
• Detection: Selected ion monitoring (SIM) targeting characteristic m/z ions for each analyte.
• Calibration: Six-point curves for PAEs (0.05–10 mg/L) and PAHs (5–100 µg/L); r2 > 0.997.

Main Results and Discussion

Linearity and Recovery:

• All calibration curves showed excellent linearity (r2 > 0.997).
• Toluene provided superior extraction compared to hexane and dichloromethane, with recoveries of 85.5–116.0% for PAEs and 85–113% for PAHs.

Migration Findings:

• Leaching increased with higher temperature and longer contact time; the highest migration was observed in 50% ethanol.
• Dibutyl phthalate (DBP) levels remained below the Chinese specific migration limit (SML) of 0.3 mg/kg; other phthalates were also below their respective limits or not specified.
• No PAHs were detected in any simulant under the studied conditions.

Benefits and Practical Applications

The validated method enables reliable monitoring of phthalates and PAHs in food-contact materials, supports compliance with regulatory standards, and aids quality assurance in food packaging industries.

Future Trends and Opportunities

Future research may focus on high-resolution mass spectrometry for non-target screening, automation of sample preparation, assessment of alternative polymers, and incorporation of digital data analysis to improve throughput and detection sensitivity.

Conclusion

The developed GC/MS procedure using a toluene extraction and SIM mode is robust and sensitive for simultaneous determination of 16 PAEs and 16 PAHs in plastic bag simulants. Migration levels were low, confirming suitability for routine safety assessment.

References

1. GB 31604.1-2015 General rules for food contact materials and articles.
2. GB 31604.30-2016 Food contact materials and articles – Determination of phthalates and migration.
3. GB 5009.265-2016 Determination of polycyclic aromatic hydrocarbons in foods.
4. GB 9685-2008 Hygienic standards for uses of additives in food containers and packaging materials.