Extractables Analysis of Food Contact Materials Using High-Resolution GC/MS and LC/MS

Importance of the topic

Food contact materials (FCM) can release volatile, semi-volatile and non-volatile chemicals into food, posing potential safety and regulatory concerns. Comprehensive characterization of extractables and leachables (E&L) from packaging—spanning plastics, paperboard and coated liners—is therefore essential for risk assessment, compliance testing and product development. Combining high-resolution gas and liquid chromatography–mass spectrometry (GC/Q-TOF and LC/Q-TOF) with application-specific accurate-mass libraries improves confidence in identification and broadens compound coverage across diverse chemical classes.

Objectives and study overview

This study evaluated extraction methods and high-resolution GC/MS and LC/MS workflows to characterize E&L from several FCM types: vacuum sealer plastic bags, heavy-duty plastic food containers, and lined paperboard containers. Objectives included comparing solvents and extraction approaches, maximizing detection of diverse migrant classes, expanding accurate-mass libraries for GC/Q-TOF E&L identification, and applying data-processing/statistical tools for comparative analysis and unknown structure elucidation.

Experimental methods

Extractions:

• Sovents tested: ethanol, ethanol:hexane (1:1), hexane, isooctane. Extractions were performed at 70 °C for 2 hours, followed by centrifugation to remove particulates.
• Thermal extraction (direct thermal desorption) was performed on small samples (~5 mg) of wax liners and paper coatings using a thermal desorption unit (GERSTEL TD) to target volatile/semivolatile liner components.

Analytical approaches:

• GC/Q-TOF analyses targeted volatile and semi‑volatile migrants and used both standard EI (70 eV) and low‑energy EI (9–15 eV) acquisition modes plus EI MS/MS for structural elucidation and spectral matching.
• LC/Q-TOF analyses (ethanol extracts) provided complementary coverage of polar, nonvolatile migrants and iterative auto MS/MS data for spectral library matching and identification.

Used instrumentation

GC/Q-TOF setup:

• Agilent 7250 GC/Q-TOF with Agilent 8890 GC.
• Column: Agilent DB-5Q (30 m × 0.25 mm × 0.25 µm). Inlet: MMI with single taper wool liner, splitless 1 µL injections.
• Temperature program: 45 °C (2 min) ramp to 325 °C; transfer line 325 °C; source ~200 °C; acquisition 50–1000 m/z at 5 Hz. Modes included 70 eV EI and low-energy EI for softer ionization.

LC/Q-TOF setup:

• Agilent 1290 Infinity II LC coupled to Agilent Revident LC/Q-TOF.
• Analytical columns: Poroshell Aq-C18 (2.1 × 150 mm, 2.7 µm) and Poroshell EC-C18 (4.6 × 50 mm, 2.7 µm). Column temp 40 °C; injection 5 µL; flow 0.35 mL/min.
• Mobile phases: water with 2.5 mM NH4Formate, 0.05% formic acid and 100 µM NH4F (A) and methanol with same additives (B). Gradient from 2% B to 100% B over ~16 min.
• MS: Dual AJS ESI, positive polarity, Auto MS/MS with collision energies 10, 20, 40 eV, MS range 40–1700 m/z; acquisition 4 spectra/s (MS) and 6 spectra/s (MS/MS).

Data processing and libraries:

• GC/MS: Agilent MassHunter Qualitative and Unknowns Analysis; statistical work in Mass Profiler Professional (MPP) 15.1.
• LC/MS: MassHunter Explorer 2.0 for batch processing and iterative MS/MS feature lists.
• Libraries: an expanded accurate-mass GC/Q-TOF E&L PCDL (>500 compounds) incorporating antioxidants, UV stabilizers, phthalates, ink/pigment components and CLAP standards; LC/MS database built with Agilent ChemVista merging online resources (EPA Comptox, Food Packaging Migration databases) and in-house/MS‑Bank spectra.

Main results and discussion

Extraction solvent performance and material-specific profiles:

• Ethanol extracts gave the broadest range of compound classes and the highest number of unique features for plastic bags and paperboard, indicating good extraction of polar and mid-polar migrants.
• For hard plastic containers, ethanol:hexane (1:1) provided the most efficient recovery across many target classes, while isooctane preferentially extracted nonpolar hydrocarbons, tert‑butyl‑containing species, branched alcohols and certain phosphite-type antioxidants (e.g., Irgafos 168 phosphate).
• Material-specific observations: plastic containers were dominated by hydrocarbons; both plastic bags and containers contained antioxidants such as Irganox 1076, Irgafos 168 and Irgafos phosphate; plastic bags additionally contained caprolactam, erucamide and cyclic nylon oligomers (dimers/trimers/tetramers) in some brands; paperboard extracts were the most chemically complex, containing long-chain alkanes (C23–C35), low‑molecular‑weight alcohols/aldehydes/ketones, diterpenoid acids and plant secondary metabolites.
• Bisphenol AF was detected across all FCM types examined; Bisphenol A was detected at trace levels in some plastic bags and containers.

Thermal desorption and liner analysis:

• Direct thermal extraction of wax liners and paper coatings distinguished volatile/semivolatile components derived from coatings versus bulk paper, revealing unique profiles (e.g., coniferyl aldehyde, higher alkanes, low-MW alcohols/aldehydes and diterpenoid acids) important for source attribution.

Data analysis and identification confidence:

• Use of the expanded GC/Q-TOF E&L PCDL (EI spectra + accurate mass metadata) and a focused LC/MS MS/MS database substantially improved annotation rates and reduced ambiguous identifications in both GC and LC workflows.
• Statistical comparisons (volcano plots, fold-change filtering, blank subtraction) allowed efficient identification of compounds that were enriched in one material or brand versus others, facilitating prioritization for further toxicological or migration assessment.
• Structure elucidation of unknowns employed low-energy EI and EI MS/MS to predict molecular ions and propose candidate structures supported by MS/MS fragmentation patterns.

Benefits and practical applications of the method

• Complementary high-resolution GC/Q-TOF and LC/Q-TOF workflows deliver broad chemical coverage from highly volatile hydrocarbons to polar, nonvolatile migrants, reducing false negatives in E&L screening.
• Application-focused accurate-mass libraries and curated LC/MS/MS databases accelerate putative identifications and increase confidence for non-target and suspect screening in regulatory and R&D contexts.
• Thermal desorption of liners and coatings is a practical tool to attribute the origin of migrants, important for corrective action in packaging design or vendor assessment.
• Combined analytical and statistical workflows support brand and material comparisons, aiding QA/QC, supplier qualification and forensic investigations of packaging-derived contaminants.

Future trends and potential uses

• Continued expansion and community sharing of accurate-mass EI and LC/MS/MS libraries focused on FCM chemistry will improve identification rates for obscure packaging additives and degradation products.
• Integration of in silico fragmentation prediction, retention index models and orthogonal ionization methods (PCI, APCI, LEEI) will strengthen structural proposals for unknowns.
• High-throughput non-target screening pipelines with automated statistical prioritization and workflows that link chemical occurrence to exposure and toxicological endpoints will support regulatory decision-making.
• Standardized extraction protocols and reference materials for coated paperboard and multi-layer laminates could harmonize inter-laboratory E&L results and risk assessment practices.

Conclusions

• A combined high-resolution GC/Q-TOF and LC/Q-TOF strategy, together with appropriate extraction selection and specialized accurate-mass libraries, provides comprehensive coverage of E&L from diverse food contact materials.
• Choice of extraction solvent is material-dependent: ethanol favored polar and mid-polar migrants (bags, paperboard), ethanol:hexane favored many analytes in rigid plastics, and isooctane extracted nonpolar hydrocarbons and branched alcohols effectively.
• Application‑specific libraries and robust data-processing/statistical workflows are critical to efficiently annotate and prioritize compounds for follow-up.

References

• Poster: ASMS 2026, WP 311 — Extractables Analysis of Food Contact Materials Using High-Resolution GC/MS and LC/MS, Sofia Nieto et al., Agilent Technologies (June 2026).
• Data-processing and spectral libraries: Agilent MassHunter Qualitative, Unknowns Analysis, Mass Profiler Professional 15.1, MassHunter Explorer 2.0, Agilent ChemVista library management.
• Standards and E&L reference materials: FDA CLAP kit and Agilent/AChemTek Food Contact E/L Standards Kits.