Separation of Lipids

Supercritical fluid chromatography (SFC) is one of the useful techniques used in lipid analysis. Since lipids comprise an enormous number of molecular species with similar structures, high-resolution chromatographic separation, coupled with mass spectrometry (MS) or other detection methods, is required for detailed profiling of molecular species. The high diffusivity and low polarity of supercritical carbon dioxide (SCCO₂) enables the separation of individual lipid molecular species with good resolution. The low viscosity of SCCO₂ allows for a high flow rate of the SFC mobile phase, resulting in shorter separation time compared with liquid chromatography (LC). In addition, polar lipids can be analyzed using gradient elution with SCCO₂ and a modifier.Supercritical fluid extraction (SFE) can be combined directly with SFC, enabling high-throughput analysis of thermally labile and oxidizable hydrophobic compounds. These supercritical fluid-related techniques have potential applications in biomarker discovery and elucidation of the detailed mechanisms of lipid metabolism.