Figure 3.

Bipolar atmospheres for charge equilibration based on ²¹⁰Po and the AC corona discharge process yield comparable results. Data for two exemplary proteins (ovalbumin, A, and thyroglobulin, B) are shown as well as data for a virus-like particle based on cowpea mosaic virus, CPMV (C), a polystyrene-based size standard (D), and a liposomal vesicle (E). EMD values are comparable in all cases. The corona discharge process yields at least comparable numbers of single-charged NPs if not higher values when compared to the ²¹⁰Po source. EMD data and a relative plot of spectra are given in the Supporting Information.