Lipids are the main components of biological membranes. Lipids are not only the main form of energy storage in living cells but also serve as mediators of cell signaling. The lipidome consists of 8 major classes, over 80 main categories, 300 subclasses, and thousands of lipids at different concentrations. Lipidomics is the systematic study of all lipid molecules (> 30,000 species) within a biological system, tissue, body fluid, or cell.