Analytical workflow for parallel analysis of mineral oil and PAHs by HPLC/GC×GC-ToFMS/FID

Mineral oil hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) are contaminants of concern in foodstuffs due to their potential impact on public health. Mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) are petroleum-derived compounds distinguished by their chemical structures. While MOSH may accumulate in adipose tissue and organs, MOAH exhibit carcinogenic potential. Polycyclic aromatic hydrocarbons (PAHs), structurally related to MOAH but originating from incomplete combustion processes, similarly exhibit carcinogenic properties.
Although MOAH and PAHs represent different contaminant classes, the same sample preparation approaches can be employed for both. Moreover, these compounds share a polyaromatic structure, with the sole distinction being that MOAH are alkylated compounds. However, the analysis of these two compound classes is traditionally performed separately using different methodologies, as MOAH require FID for accurate quantification, whereas PAHs need a more sensitive and selective detector such as a MS.
This study presents the development of a novel analytical workflow for the simultaneous analysis of these contaminants in complex matrices, such as fat and oil derived food additives, for which no analytical method has been validated to date.
Adapted from ISO 20122:2024, originally developed for MOSH/MOAH analysis in vegetable oils, the procedure has been modified to address the chemically complex composition of additives such as E471, E472, E475, E481, E322, where interfering compounds pose substantial challenges for accurate determination and compound recovery. The new workflow includes microwave-assisted saponification and extraction, followed by high-performance liquid chromatography (HPLC) fractionation to separate MOSH from MOAH and PAH fractions. To mitigate interference, MOAH are purified via chemical epoxidation. Finally, comprehensive two-dimensional gas chromatography coupled with FID and time-of-flight MS (GC×GC-FID/TOFMS) was performed.
This workflow allows the simultaneous analysis of MOSH, MOAH and PAHs, enhancing the removal of interfering compounds from complex additive matrices while meeting analytical performance requirements.