title: Identification of novel isomeric pectic oligosaccharides using hydrophilic interaction chromatography coupled to traveling-wave ion mobility mass spectrometry.
abstract: Separation and characterization of complex mixtures of pectic oligosaccharides still remains challenging and often requires the use of multiple analytical techniques, especially when isomeric structures are present. In this work, it is demonstrated that the coupling of hydrophilic interaction chromatography (HILIC) to traveling-wave ion mobility mass spectrometry (TWIMMS) enabled the simultaneous separation and characterization of complex mixtures of various isomeric pectic oligosaccharides. Labeling of oligosaccharides with 3-aminoquinoline (3-AQ) improved MS-ionization efficiency of the oligosaccharides and reduced the complexity of the product ion mass spectra, without losing resolution of the HILIC separation. In addition, labeling enabled quantification of oligosaccharides on molar basis using in-line fluorescence detection. Isomeric structures were distinguished using TWIMMS. The 3-AQ-HILIC-TWIMMS method was used to characterize a series of isomeric sugar beet rhamnogalacturonan I derived oligosaccharides carrying a glucuronic acid substituent. Thereby, some novel structural features were identified for the first time: glucuronic acid was attached to O-3 or to O-2 of galacturonic acid residues and a single galacturonic acid residue within an oligomer could contain both an acetyl group and a glucuronic acid substituent.
authors: Wageningen University, Laboratory of Food Chemistry, PO Box 17, 6700 AA Wageningen, The Netherlands; IRS, PO Box 32, 4600 AA Bergen op Zoom, The Netherlands.
authors: Antonius G M
authors: AG
authors: Leijdekkers
authors: Wageningen University, Laboratory of Food Chemistry, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors: Jie-Hong
authors: JH
authors: Huang
authors: Wageningen University, Laboratory of Food Chemistry, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors: Edwin J
authors: EJ
authors: Bakx
authors: Wageningen University, Laboratory of Food Chemistry, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors: Harry
authors: H
authors: Gruppen
authors: Wageningen University, Laboratory of Food Chemistry, PO Box 17, 6700 AA Wageningen, The Netherlands. Electronic address: henk.schols@wur.nl.
authors: Henk A
authors: HA
authors: Schols
mesh_terms: D027461:Beta vulgaris / Q000737:chemistry; D002845:Chromatography / Q000379:methods*; D020723:Glucuronic Acid / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007536:Isomerism; D013058:Mass Spectrometry / Q000379:methods*; D008958:Models, Molecular; D009844:Oligosaccharides / Q000302:isolation & purification*; D010368:Pectins / Q000737:chemistry*
chemical_list: D009844:Oligosaccharides; C042491:rhamnogalacturonan I; D010368:Pectins; D020723:Glucuronic Acid
keywords: 3-Aminoquinoline; Glucuronic acid; Pectin; Rhamnogalacturonan I; Structure elucidation; Sugar beet