Vegetable oils belong to a large group of substances obtained from plants. They can be extracted from corn, olives, rape, or sunflower. The procedures of sample preparation applied at present are based on the ICPAES and ETAAS techniques, which comply with the heavy metal determination norm, are time-consuming, and require large amounts of chemical reagents – including organic solvents. The stage of preparation of vegetable oil samples for chemical analysis causes difficulties related to the extraction of sample ingredients to the solution, which can be determined by routine methods. During the extraction, there is a high risk of contaminating the sample or the analyte. The determination of the heavy metals iron and manganese in mineral oil samples is a major challenge for an analyst because of the sample properties and the conditions of the extraction procedure.
Due to the reasons stated above, our study aimed to select the appropriate conditions to facilitate the extraction process of oil samples and to simplify the procedure in terms of equipment requirements. Moreover, the developed procedure was compared with classical extraction methods in order to be applied in the determination of metals in oils. The paper also presents the concentration variability of Cu, Zn, Pb, and Cd, as well as Fe and Mn in the production process (from rapeseed to the final market product).