Quantification and characterization of mineral oil in fish feed by liquid chromatography-gas chromatography-flame ionization detector and liquid chromatography-comprehensive multidimensional gas chromatography-time-of-flight mass spectrometer/flame ionization detector

Mineral oil is an ubiquitous food contaminant potentially toxic. It is generally divided into aromatic hydrocarbons (MOAH) and saturated hydrocarbons (MOSH). These compounds are currently under investigation by the European Union to determine their occurrence and their toxicity before legislating on the matter. Although the discussion mainly focuses on food, animal feed can indirectly contribute to human exposure to such a contaminant. In this study, seven commercial feeds were analyzed. The analyses were carried out in two different Universities (Udine-IT and Liege-BE), performing the same sample preparation protocol: microwave-assisted saponification and extraction followed by epoxidation for the MOAH fraction. The final determination was performed by hyphenated liquid-gas chromatography (LC-GC) and LC coupled to comprehensive multidimensional gas chromatography (LC-GC x GC) with parallel detection, namely flame ionization detector (FID) and time-of-flight mass spectrometer (ToFMS). The results obtained by the two laboratories were generally in good agreement. The results obtained by LC-GC x GC-ToFMS/FID platform provided consistent results, with the advantages of more robust data interpretation that can compensate for problems occurring during purification. Moreover, the coupling of enhanced separation obtained by GC x GC and the MS information allowed for a more in-depth characterization of the contamination. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study analyzed seven commercial feeds and found consistent results between two laboratories. The combination of liquid-gas chromatography and liquid chromatography coupled with comprehensive multidimensional gas chromatography, along with parallel detection using flame ionization detector and time-of-flight mass spectrometer, allowed for a more comprehensive characterization of the contaminants.