Characterisation of MOSH/MOAH results
Eurofins complements the quantification of TPAFs using two-dimensional GCxGC-FID to its portfolio of mineral oil confirmatory methods
June 2025 (update). From July 2025, the Competence Centre for Organic Contaminants of the Eurofins Laboratory Network for Food & Feed Testing in Germany will carry out the quantification of MOAH (C10-C50) and the tri- to polyaromatic fraction (TPAF) of MOAH using two-dimensional GCxGC-FID. This method complements the qualitative characterisation of MOSH/MOAH findings in food using GCxGC-TOF-MS and delivers additional information for a toxicological evaluation of mineral oil contaminations.
The advantages of the GCxGC-ToF-MS/FID at a glance
- Qualitative confirmation of positive results from quantitative LC-GC-FID analysis
- Mass spectrometric characterisation of the complex MOSH and MOAH fractions
- Possible identification of the multiple sources of mineral oil contaminants
- Identification of the number of aromatic rings and quantification of the tri- to polyaromatic fraction (TPAF) of MOAH as a basis for toxicological assessments
Why is there a need for additional methods for mineral oil analysis?
1. Toxicological and analytical background
The toxicological relevance of particularly aromatic mineral oil hydrocarbons (MOAH) has been known for many years. In 2023, EFSA described in its last Scientific Opinion on the risk assessment of mineral oil hydrocarbons in food that the genotoxicity of MOAH is related to the presence of aromatics with three or more rings. However, data on MOAH composition by ring number in food are mostly lacking.
In its Technical Report (2023), the EU Joint Research Centre (JRC) sets out guidelines for the sampling, analysis and reporting of mineral oil hydrocarbons in food. Here, a two-dimensional GCxGC analysis is explicitly recommended to determine aromatics according to their ring number and to clarify interferences in the chromatogram of classical LC-GC-FID analysis. The authorities of some EU member states already require a confirmatory analysis using two-dimensional GCxGC technology.
2. Key facts of the GCxGC-ToF-MS/FID analyses
The experts from the Competence Centre for Organic Contaminants of the Eurofins Laboratory Network for Food & Feed Testing in Germany already have many years of experience with the quantitative determination of MOSH and MOAH by online LC-GC-FID as well as characterisation by LC-GC-MS.
The introduction of the additional qualitative two-dimensional GCxGC-ToF-MS enables a more precise characterisation of the MOSH and MOAH fractions. This requires a separate analysis for each fraction.
By separating each fraction in two dimensions, the aromatics in the MOAH fraction can be separated by ring number to enable a toxicological assessment. Interferences with natural accompanying substances such as terpenes from aromas and carotenoids, occurring in the one-dimensional chromatography, can now be resolved more efficiently. In the MOSH fraction, the identification of hopanes, steranes, phytane, pristane and other characteristic markers can significantly contribute to the identification of the source of contamination.
The quantitative two-dimensional GCxGC-FID analysis of the MOAH fraction allows for the separation of the mono- and diaromatic MOAH fraction (MDAF) from the tri-to polyaromatic MOAH fraction (TPAF) and thus enables a quantification of the part of the MOAH fraction which is of toxicological concern.
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Written by:
Sabrina Hansen
Eurofins WEJ Contaminants GmbH