Ion parking

FIGURE 1.6 Gas-phase concentration of bovine serum albumin. Mass spectra derived (a) from native ESI (b) after partial proton transfer reactions and in the absence of ion parking mode and (c) after partial proton transfer reactions with ion parking mode. (Reproduced from Reid, G.E. Wells, J.M. Badman, E.R. McLuckey, S.A., Int. J. Mass Spectrom. 2003, 222, 243-258. With permission from Elsevier.)... 

Chrisman, P.A. Pitteri, S.J. McLuckey, S.A. Parallel ion parking Improving conversion of parents to first-generation products in electron transfer dissociation. Anal. Chem. 2005, 77,3411-3414. 

By relating K to the free energy change due to the approach of the 2H ions to the MO ion, Park showed that... 

A major repercussion of ion parking is that a single (lower)-charge-state ion may be accumulated at the expense of other (higher) charge states. Shown in Figure 14. ° is... 

Figure 14.7. Mass spectra of bovine cytochrome c acquired in (a) pre-ion/ion, (b) post-ion/ion (no ion parking), and (c) ion parking modes. Approximately 90% of the ions in a are accounted for in c. Of the totality of ions in c, about 83% are in the 10+ charge state. (Reprinted from Ref. 107 with permission.)...

An alternative approach to ion parking was introduced by Grosshans et al. ° ° in a pair of patent filings wherein a dipolar DC voltage was applied across the end-cap electrodes of a quadrupole ion trap. The result is a m/z-dependent separation in space of cation and anion clouds that results in the parking of aU ions above a certain miz value. 

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