General rules

  • Lipid extract concentration and solvent system used should be considered.
  • Adequate mass spectrometry conditions should be applied to avoid artefacts such as in-source fragmentation.
  • System should be checked using lipid standards, e.g. in-source fragmentation, sensitivity, linearity range and robustness.
  • Lipid biochemistry related to the sample material should be considered i.e. building blocks (e.g. fatty acids, sphingoid bases) in the mass spectrometry analysis.

 

The applied analytical approach determines the level of structural lipid detail - the preferred analyses are:

  • Sum composition, e.g. PC 34:1 - full scan MS
  • Molecular composition, e.g. PC 16:0_18:1 - tandem mass spectrometry
  • Positional isomers, e.g. PC 16:0/18:1 - ion trap MS3, separation MS etc
  • Double bond positioning, e.g. PC 16:0-18:1n9 - OzID derivatization, separation MS etc

 

Common characteristic fragment ions used for the analysis of lipid classes and molecular species.