Biodiesel, derived from vegetable feedstocks such as soybean and rapeseed or from animal fats, is a fuel commodity primarily used as a value-added blending component with diesel fuel. The term biodiesel describes a fuel of pure mono alkyl esters such as fatty acid methyl ester (FAME), and is designated B100. This application note describes how the PerkinElmer Biodiesel IR FAME Analyzer, comprising a Spectrum 3 FTIR spectrometer with the appropriate ATR or transmission accessory, and Spectrum 10 software gives the user the choice of being configured specifically for either the ASTM D7371-14 or the EN 14078:2014 methodology.