Determination of Mineral Oil Hydrocarbons in Food and Food Packaging using LC-GCxGCMS Technique

Importance of the Topic

Mineral oil hydrocarbons (MOH) originating from paper and cardboard packaging can migrate into food, posing potential health concerns. Saturated fractions (MOSH) currently lack conclusive toxicological limits, while aromatic fractions (MOAH), particularly polycyclic aromatic-like compounds, are suspected carcinogens. With no uniform legal thresholds, analytical methods that reliably quantify these contaminants are critical for food safety and regulatory compliance.

Objectives and Study Overview

This work presents an automated analytical workflow based on liquid chromatography coupled to two-dimensional gas chromatography with flame ionization detection (LC-GCxGC-FID) for quantifying MOSH and MOAH in food and packaging materials. The approach follows European Norm EN 16995:2017, demonstrating separation, cleanup, and quantitation under real-world sample conditions, including spiked rice and various food matrices.

Methodology and Instrumentation

Sample Preparation:

• Homogenized food samples (1–10 g) spiked with internal standards.
• Extraction in n-hexane with Restek MOSH/MOAH internal mix.
• Automated alumina flash cleanup to remove n-alkane interferences.
• Concentration under nitrogen and aliquot transfer to autosampler vials.

Chromatographic Separation:

• Normal-phase HPLC gradient on silica to separate MOSH and MOAH.
• Online interface directs MOSH and MOAH fractions to two GC columns.
• High-temperature GC and dual FID detection for simultaneous quantitation.

Instrumentation Used

• Shimadzu Nexera LC system (LC-40BXR pump, CBM-40A controller, SPD-40A UV detector).
• Shimadzu GC-2030 dual-FID gas chromatograph with retention gaps.
• Axel Semrau PAL autosampler and Chronos LC-GC interface.
• Alumina and silica gel for automated flash cleanup.
• LabSolutions and Chromsquare software for data acquisition and processing.

Main Results and Discussion

A 5 mg/kg MOH spike in rice yielded a MOSH reading of 10.8 mg/kg before cleanup, driven by odd-chain alkanes (C25–C35). After alumina flash purification, interferences were removed, delivering a MOSH value of 4.31 mg/kg and MOAH of 0.64 mg/kg, corresponding to a total recovery of 4.95 mg/kg. The high resolution of GCxGC-FID enabled clear fractionation and precise quantitation. Comprehensive GCxGC-MS further aids in identifying MOAH subcomponents and excluding false positives from other hydrocarbon sources.

Benefits and Practical Applications

• Fully automated sample cleanup and online LC-GC coupling reduce manual steps and increase throughput.
• High chromatographic resolution separates target fractions from complex food matrices.
• Compliance with EN 16995:2017 supports regulatory monitoring and quality control.
• Adaptable to a variety of food and packaging types for routine surveillance.

Future Trends and Potential Applications

Advancements are expected in software-driven data analysis and further integration of LC-GCxGC-MS workflows. Regulatory frameworks may evolve to set specific MOH limits, driving method standardization. Emerging functional barrier materials and rapid in-line monitoring solutions will complement analytical efforts and help minimize MOH migration.

Conclusion

The described LC-GCxGC-FID method provides a robust, high-throughput solution for MOSH and MOAH determination in food and packaging according to EN 16995:2017. Its automated cleanup, dual-dimensional separation, and sensitive detection make it suitable for routine compliance testing and research applications.

References

1. Commission Recommendation (EU) 2017/84 of 16 January 2017.
2. EFSA Panel on Contaminants in the Food Chain, "Mineral Oil Hydrocarbons in Food," EFSA Journal 2012;10(6):2704.
3. EN 16995:2017, Determination of MOSH and MOAH by on-line HPLC-GC-FID.
4. Biedermann M. and Grob K., On-line coupled HPLC–GC for mineral oil analysis, J. Chromatogr. A 2011;1255:56–75.
5. BfR Report, "Determination of hydrocarbons from mineral oil or polymers," 2017.