The SAII was softer than the ESI, and the magnitude of the difference depends on the voltage applied to the tube lens and skimmer. The average internal energy obtained by SAII was 87% or 65% of that obtained by ESI, and the difference was greater at large skimmer voltages. This means that these voltages influence more the ion internal energies in ESI than SAII. The interpretation is that SAII droplets are less charged on average, take longer to desolvate, and therefore, ions are protected longer from direct in-source collisional activation.