Arrival time distributions of product ions reveal isomeric ratio of deprotonated molecules in ion mobility–mass spectrometry of hyaluronan‐derived oligosaccharides

Hyaluronic acid is a naturally occurring linear polysaccharide with substantial medical potential. In this work, discrimination of tyramine-based hyaluronan derivatives was accessed by ion mobility–mass spectrometry of deprotonated molecules and nuclear magnetic resonance spectroscopy. As the product ion mass spectra did not allow for direct isomer discrimination in mixture, the reductivelabeling ofoligosaccharidesaswell asstable isotope labelingwasperformed. The ion mobility separation ofparent ions together with the characteristic fragmentation for reduced isomers providing unique product ions allowed us to identify isomers present in a mixture and determine their mutual isomeric ratio. The determination used simple recalculation of arrival time distribution areas ofuniqueions toareasofdeprotonatedmolecules. Massspectrometrydatawere confirmedbynuclear magneticresonance spectroscopy. Copyright © 2015 John Wiley & Sons, Ltd. Additional supporting information may be found in the online version of this article at the publisher’s web site.