Table 1.
Evaluation of the repeatability, retention time variation and the linearity (from 10 to 1000 ng mL−1) of the 22 internal standards, representative of the five lipid categories
| Lipid category | Repeatability (RSD, %) | Retention time variation (RSD, %) | Linearity R² |
|---|---|---|---|
| Free fatty acids | |||
| C14:0(OH) | 5.8 | 1.1 | 0.997 |
| Sphingolipids | |||
| d18:1/12:0 Cer | 3.9 | 0.7 | 0.999 |
| d18:1/12:0 GalCer | 4.7 | 0.7 | 0.999 |
| d18:1/12:0 lacCer | 3.1 | 0.7 | 0.999 |
| d18:1/12:0 Su | 3.8 | 0.4 | 0.998 |
| d18:0/12:0 SM | 5.1 | 0.7 | 0.999 |
| GM3 CD3 | 2.8 | 0.3 | 0.997 |
| Glycerophospholipids | |||
| 11:0 LPC | 10.6 | 1.7 | 0.992 |
| 14:0 LPA | 18.5 | 1.9 | 0.979 (50–1000 ng mL−1) |
| 13:0 LPE | 6.5 | 0.8 | 0.995 |
| 13:0 LPS | 5.8 | 2 | 0.997 |
| 13:0 LPI | 10.3 | 1.7 | 0.979 |
| 13:0 LPG | 7.6 | 1 | 0.989 |
| 26:0 PC | 10.6 | 0.7 | 0.985 |
| 24:0 PA | 8.9 | 0.7 | 0.998 |
| 24:0 PE | 6.5 | 0.2 | 0.990 |
| 34:1 D31 PS | 4.9 | 0.2 | 0.996 |
| 36:0 PI | 7.8 | 0.4 | 0.986 |
| 24:0 PG | 7.8 | 0.4 | 0.994 |
| Glycerolipids | |||
| 1,3-28:0 D5 DG | 20.1 | 0.7 | 0.974 |
| 60:1 D5 TG | 16.9 | 0.5 | 0.935 (50–1000 ng mL−1) |
| Sterol lipids | |||
| 22:0 cholesteryl ester | 14.8 | 0.5 | 0.981 (100–1000 ng mL−1) |