Elemental determination in Fuels and Biofuels: The Challenges and Opportunities for Analytical Chemistry

While the fossil fuel industry continues to face upheavals, with discoveries of new fields, the global demand for energy and fuels drives research into alternative and renewable energies, such as biomass. This trend has been reinforced by recognizing the negative impacts of burning fossil fuels and using fossils as raw materials for industry to supply everyday demands. In this scenario, analytical methods that are already established in laboratories worldwide must be updated to align with the trends and advances, providing new methods for the unique demands of this instigating sector, which has peculiar compositions and a broad scope of analytes. Heavy and light crude oil, coal, gas, different biomass types and their derived products are challenging samples that require experience and rigorous protocols for chemical characterization. In terms of composition, petroleum from different reservoirs presents variations in chemical composition, both in their major hydrocarbons and in the types of elements present.1 In contrast, biomass encompasses a diverse range, including lignocellulosic raw materials, waste, garbage, and agro-industrial residues, among others. This results in a diversity of compositions that significantly differ from hydrocarbon mixtures typical of fossil raw materials. Figure 1 summarizes the key aspects relevant to each context. When it comes to elemental composition, it is worth mentioning that the elements that most deserve attention in fossil raw materials and their fractions/products due to their presence and inherent impacts, in addition to sulfur (and nitrogen), are nickel and vanadium, alkaline and alkaline earth elements in petroleum and arsenic, cadmium, lead and mercury (in coal and natural gas).3 In biomass raw materials and in the products and fractions derived from their conversion, the primary elements of interest are typically sodium, potassium, calcium, magnesium, aluminum, iron, copper, phosphorus, sulfur and chlorine.