Table 2. Categorization of Lipids in Positive and Negative Ionization Mode Measured by Direct Infusion High-Resolution Mass Spectrometry in PROMISa.
| overall lipid category | lipid main class | lipid subclass | no. (%) of lipids |
|---|---|---|---|
| Fatty acyls (FA) | Fatty acids and conjugates | Free fatty acids (FreeFA) (−) | 22 (5.0%) |
| Glycerolipids (GL) | Diradylglycerols | Diacylglycerols (DG) (+) | 19 (4.3%) |
| Triradylglycerols | Triacylglycerols (TG) (+) | 56 (12.6%) | |
| Glycerophospholipids (GP) | Glycerophosphates | Phosphatic acids (PA) (−) | 20 (4.5%) |
| Phosphatic acids (PA) (+) | 13 (2.9%) | ||
| Glycerophosphocholines | Lysophosphocholines (LysoPC) (+) | 8 (1.8%) | |
| Phosphatidylcholines (PC) (−) | 52 (11.7%) | ||
| Phosphatidylcholines (PC) (+) | 54 (12.2%) | ||
| Glycerophosphoethanolamines | Phosphatidylethanolamines (PE) (−) | 24 (5.4%) | |
| Phosphatidylethanolamines (PE) (+) | 16 (3.6%) | ||
| Glycerophosphoglycerols | Phosphatidylglycerols (PG) (−) | 5 (1.1%) | |
| Glycerophosphoinositols | Phosphatidylinositols (PI) (−) | 25 (5.6%) | |
| Glycerophosphoserines | Phosphatidylserines (PS) (−) | 22 (5.0%) | |
| Sphingolipids (SP) | Ceramides | Ceramides (Cer) (−) | 16 (3.6%) |
| Phosphosphingolipids | Sphingomyelins (SM) (−) | 51 (11.5%) | |
| Sphingomyelins (SM) (+) | 27 (6.1%) | ||
| Sterol lipids (ST) | Sterols | Cholesterols and derivatives (Chol) (+) | 2 (0.5%) |
| Cholesteryl esters (CE) (+) | 12 (2.7%) | ||
| Total lipids | 360 |
a
(+) denotes lipids measured in positive ionization mode; (−) denotes lipids measured in negative ionization mode. Note the final total takes into consideration the detection of some lipids in both positive and negative mode, multiple adducts, and the possibility of multiple annotations.