title: Differentiation of underivatized diastereomeric hexosamine monosaccharides and their quantification in a mixture using the kinetic method under electrospray ionization conditions.
abstract: A simple method to differentiate underivatized diastereomeric hexosamine monosaccharides, glucosamine, galactosamine, and mannosamine is reported by applying the kinetic method using N-acetylhexosamines or naturally occurring amino acids as reference bases under electrospray ionization conditions. The observed differences to distinguish the diastereomeric hexosamines are found mainly due to the proton affinity (PA) differences between the analyte and the reference base. The PA values of the hexosamines are not available in the literature, and hence, we estimated them by the kinetic method using N-acetylhexosamines as reference bases. The determined PA values are 223.97 kcal/mol for glucosamine, 224.99 kcal/mol for mannosamine, and 224.71 kcal/mol for galactosamine. The similar PA values were also obtained by using amino acids as reference bases. We have applied the same methodology to quantify these hexosamines in a mixture following the three-point calibration method suggested in the literature.
authors.affiliation: National Center for Mass Spectrometry, Indian Institute of Chemical Technology, Hyderabad-500 007, India.
authors.forename: V
authors.initials: V
authors.lastname: Nagaveni
authors.forename: S
authors.initials: S
authors.lastname: Prabhakar
authors.forename: M
authors.initials: M
authors.lastname: Vairamani
mesh_terms: D002138:Calibration; D006595:Hexosamines / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D009005:Monosaccharides / Q000032:analysis / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods* / Q000592:standards; D013237:Stereoisomerism
chemical_list: D006595:Hexosamines; D009005:Monosaccharides; D009942:Organometallic Compounds