ELECTROSPRAY ION SOURCE

摘要

An on-axis ion source has an ionization chamber and an adjacent low-pressure region The on-axis ion source also includes a capilla tube (20) having an axial bore for supporting fluid communication between the ionization chamber and the adjacent low-pressure region, the axial bore of the capillary tube (20) being substantially concentrically aligned with the orifice (36) of a skimmer (38) loc downstream in the ion path from the capillary tube (20) A blocking element (50) is provided in an aligned facing arrangement with axial bore of the capillary tube (20) and on an opposite side of the orifice (36) relative to the capillary tube (20) The blocking eleme (50) receives droplets or particles flowing through the axial bore of the capillary tube (20) and passing through the orifice (36) of th skimmer (38) The combination of an on-axis arrangement and the use of a blocking element (50) results in improved signal-to-nois level due to enhanced ion transmission and reduction of noise arising from passage ofundesolvated droplets and particles to the mas analyzer