Multi-elemental analysis of oil renewable fuel feedstock

The use of oils and fats, mainly from non-edible or used sources, microalgae, plastic wastes, and lignocellulosic residues as feedstock to elaborate different kinds of renewable fuels (biodiesel, hydrotreated vegetable oils, pyrolysis oils, and bio-oils) is increasing with the aim of implementing a circular and dynamic economy. Quality control of these materials involves the quantification of trace elements. Their presence, even at trace levels, leads to environmental concerns, fuel instabilities and may impact the performance of combustion engines. Therefore, in order to circumvent these problems, accurate and sensitive analytical techniques are required to control the level of these elements with good precision. The present manuscript will review different analytical tools used to analyze these samples. Because of their high sensitivity, low limits of detection, wide dynamic range, and in some cases the capability of carrying out multi-elemental analyses, the review is mainly focused on inductively coupled plasma techniques. Furthermore, sample preparation procedures (e.g., direct dilution, emulsification, extraction, and matrix decomposition) are elaborated. At the end of the work, suggestions on procedures for multi-elemental determination in the aforementioned samples are provided.The authors wish to thank Total Research and Technology Gonfreville and the Spanish Ministry of Science, Innovation and Universities for the financial support (project ref. PGC2018-100711-B-I100)