title: Use of electrospray ionization ion-trap tandem mass spectrometry and principal component analysis to directly distinguish monosaccharides.
abstract: BACKGROUND
  Carbohydrates are good source of drugs and play important roles in metabolism processes and cellular interactions in organisms. Distinguishing monosaccharide isomers in saccharide derivates is an important and elementary work in investigating saccharides. It is important to develop a fast, simple and direct method for this purpose, which is described in this study.
  
  
  METHODS
  Stock solutions of monosaccharide with a concentration of 400 μM and sodium chloride at a concentration of 10 μM were made in water/methanol (50:50, v/v). The samples were subjected to electrospray ionization ion-trap tandem mass spectrometry (ESI-MS) and the detected [2M + Na - H(2)O](+) ions were further investigated by tandem mass spectrometry (MS/MS), followed by applying principal component analysis (PCA) on the obtained MS/MS data sets.
  
  
  RESULTS
  The MS/MS spectra of the [2M + Na - H(2)O](+) ions at m/z 365 for hexoses and m/z 305 for pentoses yielded unambiguous fragment patterns, while rhamnose can be directly identified by its ESI-MS [M + Na](+) ion at m/z 187. PCA showed clustering of MS/MS data of identical monosaccharide samples obtained from different experiments. By using this method, the monosaccharide in daucosterol hydrolysate was successfully identified.
  
  
  CONCLUSIONS
  A new strategy was developed for differentiation of the monosaccharides using ESI-MS/MS and PCA. In MS/MS spectra, the [2M + Na - H(2)O](+) ions yielded unambiguous distinction. PCA of the archived MS/MS data sets was applied to demonstrate the spatial resolution of the studied samples. This method presented a simple and reliable way for distinguishing monosaccharides by ESI-MS/MS.
authors.affiliation: Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Xia
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Juan
authors.initials: J
authors.lastname: Xiao
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Gu
authors.forename: Lisheng
authors.initials: L
authors.lastname: Ding
mesh_terms: D006601:Hexoses / Q000737:chemistry* / Q000145:classification; D000432:Methanol; D010429:Pentoses / Q000737:chemistry* / Q000145:classification; D025341:Principal Component Analysis / Q000379:methods*; D012855:Sitosterols; D012965:Sodium Chloride; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D014867:Water
chemical_list: D006601:Hexoses; D010429:Pentoses; D012855:Sitosterols; D014867:Water; D012965:Sodium Chloride; C011015:lyoniside; D000432:Methanol