Using a nanoelectrospray-differential mobility spectrometer-mass spectrometer system for the analysis of oligosaccharides with solvent selected control over ESI aggregate ion formation

Abstract

Differential mobility spectrometry (DMS), also commonly referred to as high field asymmetric waveform ion mobility spectrometry (FAIMS) is a rapidly advancing technology for gas-phase ion separation. The interfacing of DMS with mass spectrometry (MS) offers potential advantages over the use of mass spectrometry alone. Such advantages include improvements to mass spectral signal/noise, orthogonal/complementary ion separation to mass spectrometry, enhanced ion and complexation structural analysis, and the potential for rapid analyte quantitation. In this report, we demonstrate the successful use of our nanoESI-DMS-MS system, with a methanol drift gas modifier, for the separation of oligosaccharides. The tendency for ESI to form oligosaccharide aggregate ions and the negative impact this has on nanoESI-DMS-MS oligosaccharide analysis is described. In addition, we demonstrate the importance of sample solvent selection for controlling nanoESI oligosaccharide aggregate ion formation and its effect on glycan ionization and DMS separation. The successful use of a tetrachloroethane/methanol solvent solution to reduce ESI oligosaccharide aggregate ion formation while efficiently forming a dominant MH ϩ molecular ion is presented. By reducing aggregate ion formation in favor of a dominant MH ϩ ion, DMS selectivity and specificity is improved. In addition to DMS, we would expect the reduction in aggregate ion complexity to be beneficial to the analysis of oligosaccharides for other post-ESI separation techniques such as mass spectrometry and ion mobility. The solvent selected control over MH ϩ molecular ion formation, offered by the use of the tetrachloroethane/methanol solvent, also holds promise for enhancing MS/MS structural characterization analysis of glycans. , also referred to as high field asymmetric waveform ion mobility spectrometry (FAIMS) [2], and field ion spectrometry (FIS) [3], is a rapidly advancing technology for gas-phase ion separation. DMS has the potential to emerge as a major stand-alone separation science technique such as LC or GC. Many researchers have focused on interfacing DMS to mass spectrometry because of its atmospheric pressure, gas-phase, continuous ion separation capabilities, and the detection specificity offered by mass spectrometry. In this study, we investigate the use of a specially designed nanoESI-DMS-MS system for the analysis of oligosaccharides. Glycosylation of proteins has been demonstrated to play a significant role in their biological function [4 -7]. Characterization of glycoprotein glycan groups is essential to understanding how they influence protein function [8 -10]. ESI-MS has become a popular analysis platform for characterizing oligosaccharides because of its compatibility with up-stream separation techniques such as liquid chromatography and capillary electrophoresis, as well as the structure-rich information provided by MS n techniques [8 -10]. In this study, we demonstrate the successful use of nanoESI-DMS-MS with a methanol drift gas modifier for the separation of o...

Characterization of simple isomeric oligosaccharides and the rapid separation of glycan mixtures by ion mobility mass spectrometry

“…Recent work from the group of Hill and coworkers [27] expands on previous research by describing the successful resolution of carbohydrate isomers with different anomeric configurations together with the use of adducts and variation of mobility gas to improve separation. Differential mobility spectrometry has been employed to study aggregate formation in the analysis of oligosaccharides [28]. Here we report the results of a combined DTIMS and TWIMS investigation of a range of oligosaccharides.…”

Liquid chromatography/electrospray ionization/ion mobility spectrometry of chlorophenols with full flow from large bore LC columns

“…This has been accomplished using ion mobility devices where the mobility analyzer is placed between the ESI source and a mass spectrometer, allowing pre-filtering or pre-selection of analyte ions over interfering ions from the mobile phase or sample matrix. Such selectivity can improve signal-tonoise ratio (S/N) and separation of isobars since ion separations by mobility often occur through differences in size, shape, and mass rather than mass alone as shown in combinations of mass spectrometry with Differential Mobility Spectrometry (DMS) [6,7] and Field Asymmetric Ion Mobility Spectrometry (FAIMS) [8][9][10]. This concept of mobility control before mass analysis has been commercialized with FAIMS and DMS analyzers operated at ambient pressure.…”

Rapid screening of pesticides from fruit surfaces: preliminary examinations using a laser desorption—differential mobility spectrometry coupling

“…Theoretical considerations and experimental results which shows the possibility of enhancing ions separation by varying pressure and RF voltage are presented in a recent publication [23]. The introduction of chemical modifiers (dopants) into DMS drift gas is more universal; successful examples of enhancing explosive ion species separation under the influence of dopants are presented in [24] and for heavy (up to m/z=1154 Da) oligosaccharide molecules ions in [25].…”