Mse data viewer

Identification and structural characterization of significant lipid features were confirmed with LipoStar(Goracci et al., 2017 (link)) (Version 1.0.4, Molecular Discovery, UK). Lipidomix standard (Avanti Polar Lipids, INC., Alabaster, AL, USA) and quality control samples were analyzed in LipoStar with the recommended data processing parameters(Goracci et al., 2017 (link)) except MS/MS signal filtering threshold was set to 20 for both positive and negative ionization mode. The precursor ion (MS) and fragment ion information obtained by data independent MS (MS^E) were automatically annotated using LipoStar database library with mass tolerances of 5 ppm and 10 ppm, respectively. Annotated lipid species with the highest score and high-confidence identification (matches between experimental and theoretical MS/MS spectra) were approved, and the identified lipids with low-confidence matches were further evaluated manually using MS^E data viewer (Version 1.3, Waters Corp., MA, USA). In case of co-eluting and isomeric lipid species (e.g., triacylglycerols), all the available fragments in MS/MS spectra data were reported. However, if fragments for fatty acyl compositions of lipids weren’t clear, the lipid species were annotated as sum of total number of carbons and double bonds (e.g. PC 32:2).