These 'novel oxylipins' arising from enzymatic or non-enzymatic processes would be completely overlooked if only a targeted analysis is to be performed, questioning the utility of adapting a targeted MRM solution based on oxPUFA data . The use of oxPUFA data along with our NEO-MSMS library can be highly valuable, both for annotating compounds found in biological matrices and for connecting new structures to discover potential novel biomarkers. The very precise nature of OxPUFA data also likely suggest its use for machine-learning based annotation .