A detailed description of SELINA (shown schematically in Fig. ) has been published previously. Briefly, charged particles from a nano-electrospray pass through a 20 mm long sampling capillary (SC ) heated to approximately 200 °C for vesicles desolvation and continue moving through an aerodynamic system consisting of a flow tube with a plenum chamber by gradually losing their initial momentum in collisions with gas molecules. The particles are subsequently dragged by the jet of air into a first (upstream) quadrupole (UQ). This quadrupole is equipped with slanted wires between rods to impose an electric drift field at a pressure of 1 hPa. The charged particles are further thermalized in collisions with air molecules to the electric potential of UQ and guided via an orifice with a diameter of 1 mm into a differentially pumped chamber (5×10 -5 hPa) which accommodates a linear quadrupole trap operated as a downstream quadrupole filter (DQ). Finally, the third differentially pumped chamber contains a single-pass charge detector (CD) to measure the particle's charge and m/z. The electronics of the CD acquire a transient signal of the image charge induced by a particle flying through a 50 mm long charge pick-up metal tube.