Evaluation of storage stability of soybean biodiesel using a flame ionization detector coupled to a gas chromatography system

Background Biodiesel, an alternative energy source, has been attracting increasing worldwide interest in recent decades. It is obtained by base-catalyzed transesterification, resulting in a final mixture consisting of mono-alkyl esters and other by-products (e.g. glycerol, alcohol, free fatty acids). This composition provides a level of operational quality control that enables biodiesel to be marketed efficiently, because its viability depends on several factors, such as stability during the storage period. Unlike fossil fuels, which are relatively inert and therefore undergo few alterations to their properties during storage, biodiesel degrades through oxidation and hydrolysis, with consequent alterations to its properties, due to exposure to the environment. Thus, the purpose of this study was to monitor soybean biodiesel quality using a flame ionization detector (FID) coupled to a gas chromatography (GC) system.