Determination of testosterone and epitestosterone glucuronides in urine by ultra performance liquid chromatography-ion mobility-mass spectrometry.

UPLC-ion mobility spectrometry separations combined with mass spectrometry (UPLC-IM-MS) and tandem mass spectrometry (UPLC-IM-MS/MS) have been investigated for the simultaneous determination of testosterone and epitestosterone glucuronides in urine. The glucuronide epimers of testosterone and epitestosterone were separated by ion mobility spectrometry prior to mass analysis on the basis of differences in their collision cross sections, which have been measured in nitrogen. Combining ion mobility separation with UPLC/MS enhances the analysis of these low-abundance steroids in urine by selective interrogation of specific retention time, mass-to-charge and mobility regions.

Determining the topology of virus assembly intermediates using ion mobility spectrometry-mass spectrometry.

We have combined ion mobility spectrometry-mass spectrometry with tandem mass spectrometry to characterise large, non-covalently bound macromolecular complexes in terms of mass, shape (cross-sectional area) and stability (dissociation) in a single experiment. The results indicate that the quaternary architecture of a complex influences its residual shape following removal of a single subunit by collision-induced dissociation tandem mass spectrometry. Complexes whose subunits are bound to several neighbouring subunits to create a ring-like three-dimensional (3D) architecture undergo significant collapse upon dissociation.

Deciphering drift time measurements from travelling wave ion mobility spectrometry-mass spectrometry studies.

Detailed knowledge of the tertiary and quaternary structure of proteins and protein complexes is of immense importance in understanding their functionality. Similarly, variations in the conformational states of proteins form the underlying mechanisms behind many biomolecular processes, numerous of which are disease-related. Thus, the availability of reliable and accurate biophysical techniques that can provide detailed information concerning these issues is of paramount importance.