Ultra-fast mixing

The cloud of gas-phase ions moving toward the mass analyzer is a very dilute matrix while ions of the same charge are unlikely to react with each other. So, unless the generated ions undergo in-source or post-source decay, or are purposefully reacted with gas molecules/ions or irradiated, they can make their way to the detector. To estimate or confirm the duration of incubation in ultra-fast mixing approaches, one often utilizes indicator reactions with well-characterized kinetics, such as the reaction of 2,6-dichloro-phenolindophenol and ascorbic acid (e.g., [98, 101]). 

Mass Spectrometry Strategies for Ultra-fast Mixing and Incubation... 

Solvent Effect on Ultra-fast Electron Transfer in Mixed-Valence Biferrocene Monocation. 

B. Raguenet, G. Tricot, G. Silly, M. Ribes, A. Pradel, Revisiting the mixed glass former effect in ultra-fast quenched borophosphate glasses by advanced 1D/2D sohd state NMR,. Mater. Chem. 21 (2011) 17693-17704. 

While third-harmonic generation probes the intrinsic ultra-fast electronic response of the system, degenerate four-wave mixing, by measuring the nonlinear diffraction efficiency of the medium, is monitoring not only the instantaneous electronic response but also the nonlinear response of the photo-induced excitations (intra and intermolecular vibrations, acoustic phonons etc.) in which the system (decays in time once the excited states have been prepared (i.e. in resonance). The... 

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