Three ways that allow us to classify the compounds can be observed depending on the relationships between structures. Firstly, the compounds are classified by families. For example, it can be observed the F families of isoprostanes or prostaglandins colored in cyan and grouped together. The linear compounds (non-cyclic) in orange are linked together by series, while the remaining prostaglandin families of types A, B, J, E, D, K, H, or I are classified separately and presented in violet color. Secondly, on the other hand, the classification of these compounds is also influenced by the number of hydroxyl groups (OH) present in the molecule, excluding the acidic part. For instance, although 13,14-dihydro-19-hydroxy-PGE1 belongs to the E family, it is found within the cluster of F families (top right corner). This can be attributed to the presence of three free OH groups in this molecule leading to fragments resembling the F family. Lastly, the presence of ketone or hydroperoxide forms, indicated by red color contours (middle left corner in violet). Oxylipins/NEO-PUFAs with 18 Da difference will likely be linked in a molecular network if they are either lipid-hydroperoxide and its corresponding ketone. Similarly, because of similarity in fragmentation patterns, it is also the case for D/E-PG derivatives and their corresponding A/J-PG like isomers.