Annotation of novel lipid structures should be based on substantial evidence:

  • interference from isomeric and/or isobaric lipid species must be excluded
  • experimental data should comprise analysis of fragment ions providing information on lipid class and respective structural elements collected in both positive and negative ion mode (when ionizable)
  • when structures for novel lipid classes are proposed:
    • the structure should be validated by comparison with a synthetic standard
    • when such a standard is not available, it should be purified and analyzed by nuclear magnetic resonance (NMR) spectrometry