The MS Facility has four ion mobility enabled mass spectrometers (see instruments page for more information). Ion mobility spectrometry enables separation of analytes according to their shape and charge allowing ions with the same molecular mass but different cross sectional area to be separated and detected. Combining IMS with MS is a powerful technique used for investigating how the size and shape of biologically releavant molecules change under different stimuli or conditions. IMS-MS can be used to measure cross sections of multimeric non covalent protein complexes for example during amyloidogenic fibril formation or the complex intermediates that form during virus capsid formation. Conformational changes in the presence and absence of specific and non-specific ligands can be also be probed.
The instrumentation in the Facility uses Travelling Wave Ion Mobliity (TWIMS) where ions are propelled through a buffer-filled ion guide by a 'travelling wave' potential that is applied sequentially to ring electrodes. As the ions traverse the ion guide propelled by the wave they undergo multiple collisions with the buffer gas. The shape and charge on the analyte will determine the magnitude of the interaction with the buffer gas, if this is sufficient it will retard the mobility of the analyte and cause it to 'roll over' the top of the wave. In this manner, analytes are separated and subsequently detected by the mass spectrometer. With careful calibration of the TWIMS device the collisional cross sectional areas of analytes can be determined.
If IMS-MS could be applied to your reserach, please contact the Facility with some details about the project and we can arrage to discuss sample requirements and costing. Email firstname.lastname@example.org for more information.