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).