ELECTROSPRAY INTERFACE FOR LIQUID CHROMATOGRAPHS AND MASS SPECTROMETERS

Electrospraying LC effluent into a dry bath gas creates a dispersion of charged droplets which rapidly evaporate. As the droplets grow smaller the increase in surface charge density and the decrease in radius of curvature result in electric fields strong enough to desorb solute ions. Part of the resulting dispersion of ions in bath gas passes through a small orifice or channel into an evacuated region to form a supersonic free jet. The core of this jet passes through a conical skimmer orifice and transports the ions to the inlet of a mass analyzer. The reported results suggest that from the standpoints of flexibility, convenience, sensitivity, cleanliness, and ease of maintenance, this ESPI source may comprise an effective and practical LC-MS interface.