title: The selected matrix influences the matrix-assisted laser desorption/ionization time-of-flight mass spectral patterns of partially deuterated glycosaminoglycan disaccharides.
abstract: BACKGROUND
  If carbohydrates are investigated by nuclear magnetic resonance (NMR) spectroscopy, they are normally dissolved in deuterated solvents, such as D2 O. The incorporation of deuterium leads to a high complexity of subsequently recorded mass spectra and reduced sensitivity because different deuterated ions become detectable. Here, we demonstrate that the applied matrix-assisted laser desorption/ionization (MALDI) matrix solution has a considerable impact on the observed isotopic distribution.
  
  
  METHODS
  Unsaturated disaccharides of chondroitin (CS) and dermatan sulfate (DS) were prepared by enzymatic digestion of the polysaccharides in D2 O and analyzed by MALDI time-of-flight mass spectrometry (TOF MS) using 2,5-dihydroxybenzoic acid (DHB) and 9-aminoacridine (9-AA) according to previously published protocols.
  
  
  RESULTS
  The extent of deuteration of a given compound can be easily determined by using the mass shift between the non-deuterated and deuterated ions. However, such a determination is more difficult when considering sugars due to their high content of exchangeable groups. Therefore, both the solvent and the matrix have a considerable impact on the MS patterns. Additionally, there are significant differences if the spectra are recorded at different laser fluences.
  
  
  CONCLUSIONS
  Great caution should be taken when the deuterium content of disaccharides is determined by MALDI MS. Aside from the use of non-protic solvents, DHB is the matrix of choice, whereas 9-AA shows a considerable influence on the observed isotope pattern in dependence on the applied laser fluence. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: University of Leipzig, Medical Faculty, Institute of Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Leipzig, Germany. ariane.nimptsch@medizin.uni-leipzig.de.
authors.forename: Ariane
authors.initials: A
authors.lastname: Nimptsch
authors.affiliation: University of Leipzig, Medical Faculty, Institute of Medical Physics and Biophysics, Härtelstraße 16-18, D-04107, Leipzig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schiller
mesh_terms: D003903:Deuterium / Q000737:chemistry; D004187:Disaccharides / Q000737:chemistry*; D005841:Gentisates / Q000737:chemistry; D006025:Glycosaminoglycans / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004187:Disaccharides; D005841:Gentisates; D006025:Glycosaminoglycans; D003903:Deuterium