Investigation of Extracted Analytes from Packaging Materials with GC-MS and High Resolution MS

Importance of the Topic

This work addresses the critical issue of extractable and leachable compounds migrating from food packaging materials into consumables. Such migration poses risks to product quality, consumer health, and compliance with safety regulations. A comprehensive, non-targeted screening approach can reveal a broad spectrum of potential contaminants and support improved risk assessment in the food and beverage industry.

Objectives and Study Overview

The study aimed to profile and identify organic analytes leached from common packaging materials, including sealable plastic bags and a reusable plastic box. By combining nominal-mass and high-resolution mass spectrometry workflows, the authors sought to enhance confidence in compound identifications and illustrate the value of complementary ionization techniques.

Methodology and Instrumentation

Sample Preparation and Analysis

• Extraction: 100 mL of 1:1 hexane/acetone placed inside each container for 20 hours at room temperature.
• Concentration: Evaporation under nitrogen to 1 mL prior to analysis.
• Screening: General non-targeted GC-TOFMS for nominal mass data and GC-HRTOFMS with both electron ionization (EI) and chemical ionization (CI) for accurate mass measurements.

Instrumentation Used

• Gas Chromatograph: Agilent 7890 with Rxi-5ms column (30 m × 0.25 mm × 0.25 µm); temperature program 40 °C (4 min) to 330 °C at 20 °C/min.
• Nominal-Mass MS: LECO Pegasus BT, EI only, mass range 33–900 m/z, 10 spectra/s.
• High-Resolution MS: LECO Pegasus HRT, EI (33–900 m/z) and CI (60–800 m/z with CH₄ and 5% NH₃), resolution 25 000 (FWHM), 10 spectra/s.

Main Results and Discussion

A non-targeted workflow combining deconvolution, NIST library searching, retention index verification, and accurate mass formula calculations successfully resolved hundreds of analytes. Coeluting compounds such as a plasticizer (Metilox) and slip agent (palmitic acid) were separated by deconvolution. CI data provided molecular ion information absent in EI spectra, improving structural assignments. High-resolution accurate mass measurements distinguished closely related phthalate isomers; for example, HRMS confirmed diisooctyl phthalate over alternative hits. Analysis of multiple brands revealed presence of plasticizers, slip agents, surfactants, antioxidants, UV stabilizers, and transformation products. A case study of Irgafos 168 and its thermal/chemical transformation product highlighted how relative ratios could inform process control monitoring.

Benefits and Practical Applications

The integrated GC-HRTOFMS approach offers:

• Comprehensive screening of extractables and leachables in packaging materials.
• Enhanced confidence in identifications through orthogonal data: retention index, library match, and accurate mass.
• Detection of molecular ions via CI when EI signals are insufficient.
• Support for quality control, regulatory compliance, and material selection in food packaging design.

Future Trends and Applications

Emerging directions include:

• Expanded suspect and non-targeted screening using advanced HRMS platforms.
• Integration of machine-learning algorithms to accelerate peak deconvolution and identification.
• Real-time monitoring of leachable profiles during production and storage.
• Development of comprehensive, high-quality spectral and retention index libraries for packaging additives.

Conclusion

This study demonstrates a robust workflow for characterizing extractable compounds from packaging materials. By leveraging nominal and high-resolution TOFMS with both EI and CI ionizations, the methodology provides high confidence in identifying a wide range of additives and potential contaminants, aiding safety assessments and process optimization.

Reference

Humston-Fulmer EM, Binkley JE. Investigation of Extracted Analytes from Packaging Materials with GC-MS and High Resolution MS. LECO Corporation, St. Joseph, MI.