Desolvation of ions

Here, disproportionation produces a tight quadrupole A ", 2Na which weakly interacts with the solvent, in contrast to the dipoles A", Na. The gain of entropy resulting from the desolvation of ions becomes a driving force for disproportionation (173). 

The solvation (hydration) and desolvation of ions is important to the gelation process in AB cement chemistry. The large dipole moment of ion-pairs causes them to interact with polar molecules, including those of the solvent. This interaction can be appreciable. Much depends on whether the solvent molecule or molecules can intrude themselves between the two ions of the ion-pair. Thus, hydration states can affect the magnitude of the interaction. The process leading to separation of ions by solvent molecules was perceived by Winstein et al. (1954) and Grunwald (1954). 

Fig. 8.15. Illustration of the desolvation of ions, (a) Charge separation inside a protuberance, (b) continuous reconstruction of the surface allows for successive rupture of inter-molecular bonds and stepwise desolvation of the ions. Reproduced from Ref. [83] by permission. Elsevier Science, 1984.

The elder model of ion formation, the charged-residue model (CRM), assumes the complete desolvation of ions by successive loss of all solvent molecules from droplets that are sufficiently small to contain just one analyte molecule in the end of a cascade of Coulomb fissions. [9,42,84] The charges (protons) of this ultimate droplet are then transferred onto the molecule. This would allow that even large protein molecules can form singly charged ions, and indeed, CRM is supported by this fact. [23]... 

Schmelzeisen-Redeker, G. Btitfering, L. Rollgen, F.W. Desolvation of Ions and Molecules in Thermospray-MS. Int. J. Mass Spectrom. Ion Proc. 1989, 90, 139-150. 

G Schmelzeisen-Redeker, L Buffering, FW Rollgen. Desolvation of ions and molecules in thermospray mass spectrometry. Int J Mass Spectrom Ion Processes 90 139-150, 1989. 

Chmiola, J., Largeot, C., Taberna, P.-L., Simon, P., and Gogotsi, Y. Desolvation of ions in subnanometer pores, its effect on capacitance and double-layer theory. Angewandte Chemie 47(18), 2008 3392-3395. DOI 10.1002/anie.200704894. 

A 0.5-imn-ID heated stainless-steel capillary (in other API sowces from Finnigan, Fignre 5.9). The transport of ions through the (heated) capillary assists in the desolvation of ions. The transport of ions by means of a viscous gas flow through a capillary samphng device was studied by Lin and Surmer [25]. 

Rollgen FW, Nehring H and Giessmann U (1989) Mechanisms of field induced desolvation of ions from liquids. In Hedin A, Sundqvist BUR and Benninghoven A (eds), Ion Formation from Organic Solids (IPOS V), pp 155-160. New York Wiley. 

Figure 15.7. Effect of interface pressure (P) and the cone voltage (V) on the dissociation of the complex in the source region of mass spectrometer. The central region (dashed lines) in the diagram corresponds to the optimum conditions for the detection of intact complexes with appropriate desolvation of ions. (Adapted from Ref. 83.)...

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