Lipid Molecular Species Fragments
Positive ion mode
| Lipid classes | Prec. ion | FragmentNeutral loss | Annot.Level | Example | Remark |
| Glycerophospholipids | [M+H]+ | NL -FA X1:Y1(+HO)NL -FA X2:Y2(+HO)NL -FA X1:Y1(-H)NL -FA X2:Y2(-H) | Molecular lipid species | PC 16:0_18:1 | NL of fatty acid and ketene |
| LPX | see respective diradyl lipid class | Molecular lipid species | Precursor m/z 482.3LPC O-16:0*LPC 15:0** | 1 | |
| CerHexCerHex2Cer | [M+H]+ | Long chain base specific product ions: e.g. m/z 264.2685 for SPH d18:1 backbone | Molecular lipid species | Cer d18:1/16:0 |
Remarks:
- Isobaric overlap of species may require assumptions:
- *only acyl chains with even number of C-atoms
- **only ester bonds are present
Negative ion mode
| Lipid classes | Prec. ion | FragmentNeutral loss | Annot.Level | Example | Remark |
| Glycerophospholipids (except PC) | [M-H]– | FA X1:Y1(+O)FA X2:Y2(+O)additional: NL -FA X1:Y1(+HO)NL -FA X2:Y2(+HO)NL -FA X1:Y1(-H)NL -FA X2:Y2(-H) | Molecular lipid species | PX 16:0_18:1 | both acyl chain fragments should be observed;additional evidence from NL of fatty acid and ketene |
| PC | [M-CH3COO]–[M-HCOO]– | FA X1:Y1(+O)FA X2:Y2(+O)additional:NL -FA X1:Y1(+HO)NL -FA X2:Y2(+HO)NL -FA X1:Y1(-H)NL -FA X2:Y2(-H) | Molecular lipid species | PC 16:0_18:1 | both acyl chain fragments should be observed;additional evidence from NL of fatty acid and ketene |
| LPX | see respective non-lyso lipid class | Molecular lipid species | Precursor m/z 438.3LPE O-16:0*LPE 15:0** | 1 |
Remarks:
- Isobaric overlap of species may require assumptions:
- *only acyl chains with even number of C-atoms
- **only ester bonds are present