Year-end Sale % OFF 
Abstract
Ion mobility-mass spectrometry (IM-MS) is a powerful technique for structural characterization, e.g., sizing and conformation, particularly when combined with quantitative modeling and comparison to theoretical values. Traveling wave IM-MS (TW-IM-MS) has recently become commercially available to nonspecialist groups and has been exploited in the structural study of large biomolecules, however reliable calibrants for large anions have not been available. Polyoxometalate (POM) species—nanoscale inorganic anions—share many of the facets of large biomolecules, however, the full potential of IM-MS in their study has yet to be realized due to a lack of suitable calibration data or validated theoretical models. Herein we address these limitations by reporting DT-IM (drift tube) data for a set of POM clusters {M12} Keggin 1, {M18} Dawson 2, and two {M7} Anderson derivatives 3 and 4 which demonstrate their use as a TW-IM-MS calibrant set to facilitate characterization of very large (ca. 1–4 nm) anionic species. The data was also used to assess the validity of standard techniques to model the collision cross sections of large inorganic anions using the nanoscale family of compounds based upon the {Se2W29} unit including the trimer, {Se8W86O299} A, tetramer, {Se8W116O408} B, and hexamer {Se12W174O612} C, including their relative sizing in solution. Furthermore, using this data set, we demonstrated how IM-MS can be used to conveniently characterize and identify the synthesis of two new, i.e., previously unreported POM species, {P8W116}, unknown D, and {Te8W116}, unknown E, which are not amenable to analysis by other means with the approximate formulation of [H34W118X8M2O416]44–, where X = P and M = Co for D and X = Te and M = Mn for E. This work establishes a new type of inorganic calibrant for IM-MS allowing sizing, structural analysis, and discovery of molecular nanostructures directly from solution.
Highlights
Ion mobility spectrometry (IMS), combined with mass spectrometry, is an analytical technique which is able to provide considerable information beyond that available from standalone MS experiments.[1−3] A typical IMS experiment measures the time taken for ions to travel through a “drift tube”; in contrast with MS, this is partially filled with a gas and the time taken for ions to pass through, the “drift time”, is a function of both m/z and interaction with that drift gas
Observed peaks corresponding to intact ions were chosen, based on their being reliably observed in both traveling wave (TW)-Ion mobility-mass spectrometry (IM-MS) and drift tube (DT)-IM-MS instruments, across a range of conditions
Since changes in the heteroatoms do not affect the rigid POM framework structure, comparison of TWCCSN2→He values for known structures with different heteroatoms may be substituted in the orthodox IM-MS workflow, replacing comparison with simulated values and allowing the rapid structural assignment of newly discovered POM species
Summary
Ion mobility spectrometry (IMS), combined with mass spectrometry (as IM-MS), is an analytical technique which is able to provide considerable information beyond that available from standalone MS experiments.[1−3] A typical IMS experiment measures the time taken for ions to travel through a “drift tube”; in contrast with MS, this is partially filled with a gas (the “drift gas”) and the time taken for ions to pass through, the “drift time” (tD), is a function of both m/z (mass to charge ratio) and interaction with that drift gas In this way, IMS can resolve isobaric (same m/z) species that would be indistinguishable in MS and provide structural information beyond simple mass/charge ratios (m/z), on converting drift time to a collision cross-section (CCS) parameter giving information about size and conformation. Structural information may be inferred by comparing with a model, and conformational and information about the supramolecular interactions may be obtained
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
