Characterisation of MOSH/MOAH results
Eurofins introduces two-dimensional GCxGC-TOF-MS as a confirmatory method
June 2024. From July 2024, the Competence Centre for Organic Contaminants of the Eurofins Laboratory Network for Food & Feed Testing in Germany will carry out the further qualitative characterisation of MOSH/MOAH findings in food using GCxGC-TOF-MS.
The advantages of the new method 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 as a basis for toxicological assessments
Why is there a need for an additional method 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.
2. Key facts of the GCxGC-TOF-MS analysis
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 now 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.
Handling MOSH/MOAH findings
General background information on mineral oil hydrocarbons and the current status of the procedure for setting maximum levels for MOSH/MOAH can be found in our article "Update on EU measures for handling MOSH/MOAH results".
Questions about the analysis of MOSH/MOAH by GCxGC-TOF-MS?
Do you have questions about the analysis of MOSH/MOAH by GCxGC-TOF-MS? Contact your personal account manager or get in touch with our expert Sabrina Hansen.
