To determine the fatty acid content of egg yolk lipids, fatty acid esters in egg yolk are transesterified, converting them to more volatile fatty acid methyl esters (FAMEs). These FAMEs are separated using gas chromatography (GC), detected using electron ionization mass spectrometry (MS), and identified using a mass spectral library. After integrating the GC peaks, students determine the relative amounts of FAMEs in their samples. Students then compare their results to the literature values for FAMEs in egg yolk and comment on differences between their data and the literature. Both regular large eggs and large eggs from a commercial supplier of eggs stated to be higher in polyunsaturated fatty acids (PUFA) are examined.