title: "Hypermethylation" of anthranilic acid-labeled sugars confers the selectivity required for liquid chromatography-mass spectrometry.
abstract: Analysis of the monosaccharides of complex carbohydrates is often performed by liquid chromatography with fluorescence detection. Unfortunately, methylated sugars, unusual amino- or deoxysugars and incomplete hydrolysis can lead to erroneous assignments of peaks. Here, we demonstrate that a volatile buffer system is suitable for the separation of anthranilic acid labeled sugars. It allows off-line examination of peaks by electrospray mass spectrometry. Approaches towards on-line mass spectrometric detection using reversed-phase or porous graphitic carbon columns fell short of achieving sufficient separation of the relevant isobaric sugars. Adequate chromatographic performance for isomeric sugars was achieved with reversed-phase chromatography of "hyper"-methylated anthranilic acid-labeled monosaccharides. Deuteromethyl iodide facilitates the discovery of naturally methylated sugars and identification of their parent monosaccharide as demonstrated with N-glycans of the snail Achatina fulica, where two thirds of the galactoses and a quarter of the mannoses were methylated.
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Windwarder
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Figl
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Svehla
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Réka Tünde
authors.initials: RT
authors.lastname: Mócsai
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Farcet
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Erika
authors.initials: E
authors.lastname: Staudacher
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Paul
authors.initials: P
authors.lastname: Kosma
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna; Muthgasse 18, 1190 Vienna, Austria. Electronic address: friedrich.altmann@boku.ac.at.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Altmann
mesh_terms: D002241:Carbohydrates / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D056148:Chromatography, Reverse-Phase / Q000379:methods; D005453:Fluorescence; D008745:Methylation; D009005:Monosaccharides / Q000032:analysis* / Q000737:chemistry; D009862:Online Systems; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D062367:ortho-Aminobenzoates / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D009005:Monosaccharides; D012997:Solvents; D062367:ortho-Aminobenzoates; C031385:anthranilic acid
keywords: 6-Deoxy talose; Anthranilic acid; Mass spectrometry; Monosaccharide; O-methylation