US Patent 7960711 Field-free electrospray nebulizer

An improved electrospray ion source for increasing the current generated from the electrospray process and of the type having a needle (10), a counter-electrode (20), a saddle or outer electrode (30), and concurrent flow of gas (92). A method and device is disclosed that utilizes a controlled electrospray nebulizer where an aerosol comprised of charged droplets and gas-phase ions is sprayed into a field-free or near field-free desolvation or reaction region (120). This process results in the production and ultimate destination of charged aerosols and gas-phase ions in field-free or near field-free regions (120, 201, 210, 240, 340) where they can be directed towards and into a sampling aperture or tube; directed into a reaction region resulting in to the production of reaction products; or directed and deposited on surfaces resulting in the production of desorbed products by means of a concurrent flow of gas or nebulizing gas (92, 94, 96), a potential difference between the regions of production and destination, counter-current flow of gas, or a combination thereof. The method is useful for increasing the detection of analytes in solutions that are electrosprayed and analyzed with mass spectrometry.