Dereplication and finding "novel" features (Figure ) is also indicative of the power of molecular networking approach for finding related metabolites. The few non-annotated nodes in this zoomed cluster, like explained above, are potential putative F-type NeuroP. For example, if we take this unknown node with the same precursor mass as F4t-NeuroP (highlighted with a star), it is relatively easy to find the missing link as the two main fragments (outside the redundant fragments described in Supplementary Information Figure ) are m/z 113.0608 and m/z 141.0557 indicative of the 7-series (Supplementary Information Figure ). Thus, several compounds have been putatively annotated with a F-prostane ring including DHA, EPA, AA, and ALA precursors. Phosphite oxidation. Trimethyl phosphite or triphenyl phosphite is known to reduce hydroperoxide derivatives and also interestingly to selectively reduce the isobaric NEO-PUFAs bicyclic-endoperoxides (like PGG) versus the more stable linear endoperoxides (1,2dioxolanes). It allowed to potentially locate those functions and/or structures (PGG like) in clusters of metabolites (Supplementary Information Figure ).