After loading the emitter with the vesicle sample, DQ in non-resolving mode was used to transfer charged vesicles toward the charge detector. To obtain m/z, charge and mass distributions of the vesicles, three DQ frequencies, i.e., 24.7 kHz, 15.6 kHz and 7.8 kHz (corresponding to m/z settings 2×10 5 , 5×10 5 , 2×10 , respectively) were used. Each frequency setting was repeated in a cycle with 30 s dwell time. Fig. shows that the vesicle m/z distributions roughly span the range from 2×10 5 to 3×10 . Because of the close similarities of the different charge distributions (Fig. ), the shape of the corresponding mass distributions resembles that of m/z (Fig. ). The distributions of LUV diameter (Fig. ) were calculated from the mass under the assumption of the spherical shape of LUVs and having a density of water (997 kg/m 3 ). In comparison with the DLS measurement (Fig. ), the diameter distributions are slightly shifted to the lower values, but most abundant diameters are in the same 100-200 nm range. The five m/z settings were then selected to acquire separate mass distributions of LUVs with a diameter between 75 and 225 nm using DQ, now in the mass-resolving mode. The resulting m/z, charge, mass, and diameter distributions are shown in Fig. . Once more, due to the similarity of charge distributions (Fig. ), the mass distributions (Fig. ) are determined primarily by that of m/z (Fig. ). The m/z resolution calculated as a ratio of the m/z peak position and its FWHM is about 5 and did not change substantially when the DQ resolution settings were increased (see Fig. ). This means, in turn, that the peak width is resulted in several distinct charge sub-populations. 12, 27 Fig. shows the time series of the vesicle detection frequencies in non-resolving and resolving regimes. The vesicles leave DQ through a 2 mm ID orifice and fly about 5 cm toward the 2 mm ID differential pumping orifice into the charge detector vacuum chamber, and then an additional 5 cm toward the 2 mm ID entrance orifice into the charge detector. Though gasfilled DQ focuses charged vesicles on the instrument axis, some divergence is expected at CD, thus lowering the number of detection events.