Thoughtful optimization of microwave-assisted saponification and extraction of MOSH&MOAH in edible oil

The analysis of mineral oil hydrocarbons (MOH) in food is a challenging task, mainly due to the high complexity of the matrices and the high affinity of mineral oil with the lipid fraction and its components. The sample preparation step represents a critical point as both time-consuming and prone to recovery loss. Nevertheless, even when dealing with edible oils it is indispensable to enrich the fraction of interest and remove potential interferences.The aim of this work is to improve the throughput of the enrichment step by performing a single step microwave-assisted extraction and saponification (MASE). The choice of the conditions and the solvents have been carefully studied to maximize the yield, the saponification efficiency, and avoid bias due to the different partition of the internal standards (ISs) in the different phases. The mixture of ethanol/water (1:1) showed the best performances in terms of saponification efficiency and ISs partition and it has been studied further to evaluate the effective extraction yield for MOSH and MOAH spiking different edible fats (coconut oil, sunflower oil, extra virgin olive oil and palm oil). The analysis well all performed exploiting the highly informative LC-GC×GC-TOFMS/FID platform.