Figure 4.
Hydrophilic interaction liquid chromatography coupled to electrospray ionization mass spectrometry (HILIC-ESI/MS) chromatograms. (A) Reconstructed ion current (RIC) chromatograms of detected lipid subclasses (m/z 50–1500) in human plasma using both positive (bottom red line) and negative (upper blue line) polarity modes. (B) Chromatogram illustrating separation of sn-1 (i.e., 1-LPI and 1-LPE) and sn-2 (i.e., 2-LPI and 2-LPE) regioisomers of lysophospholipids. Abbreviations: (lyso)phosphatidylinositols, (L)PI; (lyso)phosphatidylethanolamines, (L)PE; isoglobotetraosylceramides (iGb4), and fatty acids (FA).