Label-Free Absolute Quantitation of Oligosaccharides Using Multiple Reaction Monitoring

摘要: An absolute quantitation method for measuring free human milk oligosaccharides (HMOs) in samples was developed using multiple reaction monitoring (MRM). To obtain the best sensitivity, instrument conditions were optimized to reduce source and postsource fragmentation prior quadrupole transmission. Fragmentation spectra of HMOs collision-induced dissociation studied characteristic fragments. At least two MRM transitions used quantify identify each structure same run. The fragment ions corresponded production singly charged mono-, di-, trisaccharide sensitivity accuracy determined, with detection limit femtomole level calibration range spanning over 5 orders magnitude. Seven commercial HMO standards create curves determine a universal response all HMOs. factor estimate amounts other structures total oligosaccharide content milk. applied 20 variations concentrations from women classified as secretors nonsecretors, phenotype that can be identified by concentration 2'-fucosylation their