Simultaneous profiling of polar lipids by supercritical fluid chromatography/tandem mass spectrometry with methylation.

Supercritical fluid chromatography/tandem mass spectrometry (SFC/MS/MS) with methylation was used for the simultaneous profiling of diverse polar lipids in a mixture. A high throughput, high resolution analysis of nineteen classes of polar lipids including phospholipids, lysophospholipids, and sphingolipids was performed in 6 min. Methylation by trimethylsilyl-diazomethane suppressed peak tailing and improved detection sensitivity of phosphatidylserine (PS), phosphatidic acid (PA), lysophosphatidylserine (LPS), lysophosphatidylinositol (LPI), lysophosphatidic acid (LPA), ceramide-1-phosphate (Cer1P), sphingosine-1-phosphate (So1P), and sphinganine-1-phosphate (Sa1P). The limits of detection for PS, PA, LPS, LPI, LPA, Cer1P, So1P, and Sa1P were enhanced 7.5-, 26.7-, 600-, 116.7-, 500-, 75-, 3000-, and 4500-fold, respectively. Global qualitative and quantitative analysis of not only the high-abundance species but also the low-abundance species in the polar lipids was achieved. When the method was applied to mouse liver, 4 PSs, 24 PAs, 3 lysophosphatidylethanolamines, 11 LPSs, 6 lysophosphatidylglycerols, 4 LPIs, 13 LPAs, 7 sphingomyelins, 11 Cer1Ps, So1P, and Sa1P were additionally analyzed. Furthermore, the quantification of various molecular species in each polar lipid was carried out.