Each feature is given a confidence level from its SIRIUS evidence, and its top structure a lipid class and species: from the lipid compound database (first block of the InChIKey) or the lipid name, else from the SIRIUS lipid annotation of its formula, else from its CANOPUS ClassyFire class. The Lipid classes page counts the features per class and level and gives the source context of the top structures.

Confidence levels (Schymanski et al. 2014) from the SIRIUS evidence alone: 3, tentative structure: the CSI:FingerID top structure with a COSMIC confidence (exact mode) at or above the threshold; 4, molecular formula: the top SIRIUS formula with a ZODIAC score, or else a normalized SIRIUS score, at or above the threshold; 5, exact mass. In silico evidence gives no level 2 or 1: those need a reference spectrum or a reference standard.

Please cite the methods you used: SIRIUS 4 (Dührkop et al., Nat Methods 2019), CSI:FingerID (Dührkop et al., PNAS 2015), COSMIC (Hoffmann et al., Nat Biotechnol 2022), CANOPUS (Dührkop et al., Nat Biotechnol 2021) with ClassyFire (Djoumbou Feunang et al., J Cheminform 2016) and NPClassifier (Kim et al., J Nat Prod 2021), ZODIAC (Ludwig et al., Nat Mach Intell 2020); levels after Schymanski et al., Environ Sci Technol 2014.