0 avis
Optimizing Native Ion Mobility Q-TOF in Helium and Nitrogen for Very Fragile Noncovalent Structures
Archive ouverte
Edité par CCSD ; American Chemical Society -
International audience. The amount of internal energy imparted to the ions prior to the ion mobility cell influences the ion structure and thus the collision cross section, and non-covalent complexes with few internal degrees of freedom and/or high charge densities are particularly sensitive to collisional activation. Here we investigated the effects of virtually all tuning parameters of the Agilent 6560 IM-Q-TOF on the arrival time distributions of Ubiquitin 7+ , and found conditions in which the native state prevails. We will discuss the effects of solvent evaporation conditions in the source, of the entire pre-IM DC voltage gradient, of the funnel RF amplitudes, and will also report on ubiquitin 7+ conformations in different solvents, including native supercharging conditions. Collision-induced unfolding (CIU) can be conveniently provoked either behind the source capillary or in the trapping funnel. The softness of the instrumental conditions behind the mobility cell were further optimized with the DNA G-quadruplex [(dG 4 T 4 G 4) 2 •(NH 4 +) 3-8H] 5-, for which ion activation results in ammonia loss. To reduce the ion internal energy and obtain the intact 3-NH 4 + complex, we reduced the post-IM voltage gradient, but this resulted in a lower IM resolving power due to increased diffusion behind the drift tube. The article describes the various trade-offs between ion activation, ion transmission, and ion mobility performance for native MS of very fragile structures.
Consulter en ligne
Suggestions
Du même auteur
