DETERMINATION OF MOSH AND MOAH BY GC×GC-TOFMS

Importance of the topic

Migration of mineral oil hydrocarbons into food products poses a growing concern for public health and regulatory agencies across the European Union. MOSH (mineral oil saturated hydrocarbons) and MOAH (mineral oil aromatic hydrocarbons) originate from packaging inks, lubricants and recycled paperboard, potentially reaching consumers through everyday foodstuffs. Reliable, high-resolution analytical methods are essential to monitor contamination levels, establish exposure limits and ensure food safety compliance.

Objectives and Overview

This study evaluates a one-run analytical approach combining comprehensive two-dimensional gas chromatography (GC×GC) with time-of-flight mass spectrometry (TOFMS). The primary goals are to achieve robust separation and accurate identification of MOSH and MOAH fractions in turmeric samples, streamline analysis workflows and demonstrate the advantages over conventional one-dimensional or heart-cut LC-GC methods.

Methodology and Instrumentation

A commercial LC-GC interface was used to fractionate samples into MOSH and MOAH prior to enrichment and injection into the GC×GC-TOFMS system. Key instrumentation and conditions include:

• GC×GC System: LECO Pegasus BT 4D with quad-jet thermal modulator and secondary oven for independent temperature control
• Primary Column: Rxi-17Sil MS (12 m × 0.25 mm i.d., 0.25 µm film)
• Secondary Column: Rxi-1HT (1.05 m × 0.25 mm i.d., 0.10 µm film)
• Temperature Program: 40 °C (1 min), ramp 5 °C/min to 360 °C (10 min)
• Modulator Offset: +15 °C; Secondary Oven Offset: +7 °C
• Injector: Splitless, 1 mL/min constant flow, 330 °C
• Transfer Line: 340 °C; Ion Source: 280 °C; Electron Energy: 70 eV
• Acquisition Rate: 200 spectra/s; Mass Range: m/z 40–700

Main Results and Discussion

The dual-polarity column setup effectively resolved MOSH and MOAH compound families, with clear chromatographic regions defined by ChromaTOF software. High acquisition rates yielded full-range, high-quality mass spectra enabling confident identification of branched alkanes, naphthenes and alkylated aromatics. Surface plots and contour diagrams illustrated distinct separation of synthetic polymer contaminants (e.g., PP, PE) from biogenic terpenoids and aromatic fractions, facilitating accurate quantification and source attribution.

Benefits and Practical Applications

This GC×GC-TOFMS approach offers several advantages over one-dimensional and LC-GC-FID workflows:

• Enhanced chromatographic resolution reduces coelution and matrix interferences
• Full-scan TOFMS enables retrospective data analysis and compound confirmation
• Automated region classification accelerates data processing and result interpretation
• Single-run analysis improves laboratory throughput and cost efficiency

Future Trends and Possibilities

Advances in modulation technology, software algorithms and high-performance TOF detectors will further refine MOSH/MOAH profiling. Integration with automated sample preparation, machine learning–driven peak classification and miniaturized GC×GC platforms may enable onsite screening of packaging materials and rapid compliance testing.

Conclusion

The LECO Pegasus BT 4D GC×GC-TOFMS system, combined with ChromaTOF classification tools, delivers a powerful, reliable method for MOSH and MOAH determination. Its superior resolution, comprehensive spectra and streamlined workflow support accurate contamination assessment and facilitate regulatory compliance in food safety laboratories.

Reference

• Pantó S, Lluch J. Determination of MOSH and MOAH by GC×GC-TOFMS. LECO European Application & Technology Centre, Berlin; LECO Instrumentos S.L. Centre, Spain.