Simultaneous analysis of MOSH/MOAH and PAHs in fat oils derived food additives using an adapted sample preparation workflow and HPLC/GC×GC-FID/TOFMS

Mineral oil saturated hydrocarbons (MOSH), mineral oil aromatic hydrocarbons (MOAH), and polycyclic aromatic hydrocarbons (PAHs) are structurally related food contaminants with potential toxicological concerns, including genotoxicity. MOAH and PAHs share a polyaromatic structure, but MOAH are alkylated, whereas PAHs are not. Despite their structural similarities, their analysis is typically performed separately due to differing analytical requirements.
This study presents a unified sample preparation workflow enabling the simultaneous determination of MOSH, MOAH, and PAHs in fats and oils-derived food additives – a category for which no validated methods currently exist. The workflow is adapted and miniaturized from the ISO 20122:2024 standard for MOSH/MOAH analysis in vegetable oils, with modifications tailored to address the complex matrices of food additives (e.g., E471, E481, E322, E473, E160a), where matrix effects and interferences pose challenges for accurate determination and compound recovery.
The method involves microwave-assisted saponification/extraction (120°C, 20 min) with an optimized solvent ratio, followed by HPLC fractionation to separate the saturated (MOSH) and aromatic (MOAH and PAHs) fractions. For interference removal, MOSH are purified using a miniaturized aluminum oxide column, while MOAH undergo either chemical epoxidation or HPLC-based purification, depending on the matrix. PAH analysis does not require chemical purification due to the high selectivity of the GC×GC-TOFMS line in the HPLC/GC×GC-FID/TOFMS system used.
Compared to ISO 20122:2024, this workflow reduces solvent and reagent consumption (~5× lower), enables the characterization of MOAH aromatic ring numbers (with three or more rings being toxicologically relevant), and improves the separation of interferences from MOSH, MOAH, and PAHs. It meets analytical performance requirements, achieving limits of quantification (<2 mg/kg for MOAH, <0.9 µg/kg for PAHs) and recoveries (80-110% for MOSH/MOAH and 50-120% for PAHs) across these tested matrices.