Anal. Chem. 2008, 80, 2506-2513
Ion Mobility Mass Spectrometry Analysis of Human Glycourinome Sergey Y. Vakhrushev,† James Langridge,‡ Iain Campuzano,‡ Chris Hughes,‡ and Jasna Peter-Katalinic´*,†
Institute for Medical Physics and Biophysics, Biomedical Analysis, University of Muenster, D-48149 Muenster, Germany, and Waters Corporation, Atlas Park, Simonsway, Manchester, M22 5PP, UK
Complex carbohydrates are macromolecules biosynthesized in nontemplate-type processes, bearing specific glycoepitopes involved in crucial recognition processes such as cell differentiation and cell-cell interactions. Chemical structure of single components in complex mixtures can be analyzed by mass spectrometry for determination of the size and sequence of monosaccharides involved, branching patterns, and substitution by fucose and sialic acids. For de novo identification of glycoforms in human urinome containing N- and O-free and amino acid-linked oligosaccharides, a novel method of ion mobility tandem mass spectrometry followed by computer-assisted assignment is described. Distinct patterns of ions nested specifically by their m/z values and their drift time are observed by IMS-MS. An additional peak capacity for identification of time-separated m/z values in the IMS TOF MS mode for differentiation of singly, doubly, and triply charged molecular ion species by ion mobility separation contributes to significant reduction of carbohydrate complexity in a given mass window. Profiling of glycoforms from human urinome represents a highly efficient approach for biomarker discovery and differential glycotarget identification, demonstrating potential for diagnosis of human diseases, as for congenital disorders of glycosylation. Ion mobility mass spectrometry (IMS) was shown to allow rapid separation of components by size, shape, and mass, where ionic species of different charge states can be isolated in different ion arrival distributions, avoiding the overlap.1 In the ion mobility process, gas-phase ions accelerated by the linear electric field, E, collide with counterflow of neutral gas, resulting to a constant drift velocity vd. The ratio between the drift velocity and the strength of electric field is defined as the mobility of an ion, K ) vd/E, valid at low electric field strength (
