2.8 Putative Metabolite Annotation and Identification
The m/z and fragmentation spectra of features were cross referenced with online metabolite databases Human Metabolome Database (HMDB), METLIN, or MassBank for putative metabolite annotation. Analytical standards were purchased where available and analyzed in parallel with biological samples to achieve a level 1 identification based on the Chemical Analysis Working Group (CAWG) guidelines on metabolomics reporting standards.
Derivatized features were identified by cross-referencing m/z and retention time with a panel of derivatized metabolites previously generated in-house by the derivatization of the mass spectrometry library of standards (MSMLS) kit, purchased from IROA technologies (Sea Girt, NJ, USA).