High-performance liquid chromatography/electrospray ionization ion-trap mass spectrometry for analysis of oligosaccharides derivatized by reductive amination and N,N-dimethylation.
Milk oligosaccharides derivatized by reductive amination with benzylamine followed by N,N-dimethylation (DMBA-oligosaccharides), were analyzed by high-performance liquid chromatography/electrospray ionization ion-trap mass spectrometry (HPLC/ESI-ITMS). Separation of DMBA-oligosaccharides was achieved on a graphitized carbon column eluted with aqueous acetonitrile and the DMBA-oligosaccharides were detected by positive-ion mode ESI-ITMS allowing sample amounts down to approximately 30fmol of single DMBA-oligosaccharides injected on the HPLC column. MS/MS operation of the mass spectrometer resulted in the detection of diagnostic fragments, mainly belonging to the Y-series, allowing differentiation between isomeric milk oligosaccharides. HPLC/ESI-ITMS/MS/MS experiments indicated the migration of fucose residues of the DMBA milk oligosaccharides to the modified reducing end glucose residue during analysis, a migration previously only observed for proton adduct ions.
Broberg
Anders
A
Swedish University of Agricultural Sciences, Department of Chemistry, PO Box 7015, SE-750 07 Uppsala, Sweden. Anders.Broberg@kemi.slu.se
D000586:Amination; D002851:Chromatography, High Pressure Liquid; D005936:Glucans; D006801:Humans; D008745:Methylation; D008895:Milk, Human / Q000737:chemistry*; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives
D005936:Glucans; D009844:Oligosaccharides; C031146:maltoheptaose; D005680:gamma-Aminobutyric Acid; C518401:4-(dimethylamino)butyric acid