quantification and characterization of mineral oil in fish feed BY LC-GC-FID and LC-GC×GC-TOFMS/FID.

Mineral oil is a ubiquitous food contaminant potentially toxic. It is generally divided into 2
classes: the aromatic hydrocarbons (MOAH) and the 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 is mainly focus on food, feed can contribute indirectly to human
exposition to such a contaminant.
In this study 22 different fish feed products were analysed (7 commercial feed, 5
feedstuff and 10 from experimental diets). The analyses were performed by LC-GC-FID
and compared by two Universities involved in this project (Udine and Liege). Further
investigation was performed by LC-GC×GC-TOFMS/FID to validate the novel proposed
quantification with such a platform and for a more detailed characterization of the
contamination [1]. Simultaneous saponification and extraction of the mineral oil fraction
was performed by microwave-assisted saponification. The extract was divided into two
aliquots to perform MOSH and MOAH analysis separately, The fraction for the MOAH
analysis underwent offline epoxidation to remove the interferents, while the MOSH
fraction was further purified by aluminum oxide when overloading alkanes were
observed. The MOSH contamination observed ranged from 7 to 30 mg/kg while the
MOAH contamination was ranging from 0.5 to 5 mg/kg. The data provided by the two
laboratories were in good agreement, as well as the quantification performed with the
LC- GC×GC-TOFMS/FID platform, along with extra characterization.