Nano-electrospray emitters were pulled with the P-2000 laser-based micropipette puller (Sutter Instrument, CA) from the 10 cm length 1 mm OD, 0.78 mm ID borosilicate glass with filament (Sutter Instrument, BF100-78-10). The puller settings resulted mostly in the 4 mm taper with a closed tip. After the sample loading the emitter was conditioned by gently touching the metal surface of the sampling capillary (SC) until the signal could be registered and no corona discharge was visible at 1.5-2 mm distance from SC. After the experiments, the emitters were inspected with a light microscope (Olympus FluoView 1000 MPE) as shown in Fig. . The tip ID varied from 3 to 20 μm. The electrostatic potential was supplied to the platinum wire (0.05 mm diameter) within the emitter filled with the sample liquid. The emitters were first loaded with 300 nm latex beads in 100 mM ammonium acetate solution to find the suitable operating parameters of the nano-electrospray (i.e., electric potential, distance toward SC, and the tip diameter). For 300 nm particles (see Fig. ), the following parameters were found: the distance between the emitter and SC of 1.5-2 mm and the emitter voltage of +1.4 kV. After the latex beads sample was consumed, the sample with vesicles was loaded by syringe into the emitter without changing its position and sprayed at the same potential. The measurement procedure was repeated for three different emitters with freshly prepared vesicle samples each time (200 mM ammonium acetate aqueous solution and original vesicles sample 1:1 by volume). The transients recorded from the charge detector at different quadrupoles settings were processed using Python with Numpy, Scipy 25 and Matplotlib libraries and details are provided in the caption of Fig. . Processed results for all three emitter-sample couples are also provided in the SI (Figs. ). Since the resulting m/z, charge, mass, and diameter distributions belonging to the different emitters did not differ substantially, we focus in the next section on the data acquired with the second emitter-sample.