Development of a polar lipid profiling method by supercritical fluid chromatography/mass spectrometry

We established a high-throughput and high-resolution analytical method based on supercritical fluid chromatography (SFC) coupled with mass spectrometry (MS) for the simultaneous profiling of diverse polar lipids in a mixture. Trimethylsilyl (TMS) derivatization was used for the analysis of ten polar lipids: phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylinositol (PI), lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), lysophosphatidylglycerol (LPG), lysophosphatidic acid (LPA), lysophosphatidylinositol (LPI), sphingomyeline (SM), and sphingosine-1-phosphate (S1P). Using the developed method, the peak tailings of PA, PI, LPA, LPI, and S1P improved, and the limit of detection of PG, PI, LPA, LPI, and S1P was enhanced by 12-, 40-, 510-, 39-, and 1490-fold, respectively. Next, in the analysis of sheep plasma, 20 minor species of PI, LPC, LPE, and SM, and 7 molecular species of LPA, LPI, and S1P were additionally analyzed. The relative ratio of the molecular species in each polar lipid was also found by quantification. Finally, the simultaneous and detail profiling of ten polar lipids was successfully performed by SFC/MS applying TMS derivatization. This developed method is particularly applicable to metabolomics, especially for targeting polar lipids.