A Fully Automatic Workflow for the Determination of Mineral Oil Hydrocarbons in Food and Food Packaging

Significance of the Topic

Mineral oil hydrocarbons (MOH) contamination of food and packaging materials has become a persistent public health concern. Saturated fractions (MOSH) can accumulate in human tissues, while aromatic fractions (MOAH) may contain potentially mutagenic and carcinogenic polycyclic aromatic compounds. Regulatory bodies such as EFSA and ISO have issued guidelines and standards to monitor and limit MOH levels in food products.

Objectives and Study Overview

This work presents a fully automated analytical workflow for the determination of MOSH and MOAH in food and food packaging. The method complies with ISO 20122:2024 and EU 16995:2022, aiming to achieve high throughput, robust separation of target fractions, and accurate quantitation via on-line HPLC-GC-FID analysis.

Methodology and Instrumentation

• Sample Preparation
  • Homogenize 1–10 g of sample (e.g., rice, butter) and spike with internal standards.
  • Extract with n-hexane under agitation (2 h or overnight).
  • Clean up via flash chromatography on alumina/silica columns (activated at 40–500 °C).
  • Concentrate extracts to ~1 mL under nitrogen.
• On-Line HPLC-GC-FID System
  • Shimadzu Nexera LC with LC-40BXR pump and CBM-40A controller.
  • SPD-40A UFLC UV detector for on-line normal-phase pre-separation.
  • GC-2030 dual-channel GC with two high-temperature columns and two FID detectors.
  • Axel Semrau Chronos interface and PAL autosampler integrated via LabSolutions software.

Main Results and Discussion

• Typical MOSH/MOAH Levels
  • Edible oils: up to 6000 mg/kg MOSH/MOAH.
  • Bakery products: ~2800 mg/kg.
  • Chocolate: ~1300 mg/kg.
  • Fish: ~1200 mg/kg.
• Fraction Separation and Interference Removal
  • Flash chromatography effectively removes odd-numbered n-alkanes (C23–C33) that interfere with MOSH quantitation.
  • Two-dimensional chromatograms illustrate clear separation of MOSH and MOAH fractions.
• Analytical Performance
  • Rice sample spiked at 5 mg/kg yielded a “false” MOSH value of 10.8 mg/kg before cleanup.
  • After alumina chromatography, measured MOSH was 4.31 mg/kg and total recovery 4.95 mg/kg (99%).

Benefits and Practical Applications

• High automation reduces manual handling and enhances reproducibility.
• Simultaneous, parallel determination of MOSH and MOAH accelerates throughput.
• Method meets current ISO and EU regulatory requirements for food safety laboratories and industry QA/QC.

Future Trends and Possibilities

• Comprehensive GC×GC-MS offers enhanced two-dimensional separation, sensitivity, and compound identification.
• Advanced data processing with software like Chromsquare will support complex matrix analyses.
• Extension to other food matrices and packaging materials to broaden monitoring scope.

Conclusion

The described fully automated HPLC-GC-FID workflow enables reliable, high-throughput quantitation of MOSH and MOAH in food and packaging. Its compliance with ISO 20122:2024 and EU 16995:2022, together with excellent recovery and interference removal, makes it a robust tool for modern analytical laboratories.

Reference

• EU Commission Recommendation (EU) 2017/84 of 16 January 2017.
• EFSA CEF Panel. Scientific Opinion on Mineral Oil Hydrocarbons in Food. EFSA Journal 2012; https://doi.org/10.2903/j.efsa.2012.2704.
• EN 16995:2017 Determination of MOSH and MOAH with on-line HPLC-GC-FID analysis.
• Biedermann M.; Grob K. On-line coupled HPLC–GC for mineral oil contamination analysis. J. Chromatogr. A 2011, 1255, 56–75.
• BfR. Determination of hydrocarbons from mineral oil or plastics. 2017.