Patent ID: 6278111
Filing Date: 2001-08-21
Classification: H01J

Abstract:
An apparatus for producing desolvated analyte ions for a mass spectrometer, the apparatus comprising:an electrospray unit receiving a liquid sample comprising analyte and discharging said analyte as a cone-jet, said electrospray unit comprising an electrospray unit housing defining a pressure region below atmospheric pressure and a desolvation unit receiving said cone-jet and outputting desolvated analyte ions produced in said desolvation unit to said mass spectrometer, wherein said electrospray unit includes:a) a capillary means for introducing a liquid sample;b) a first chamber for receiving said liquid sample, said chamber including at least a first wall in which said capillary means is situated and at least a second wall, said chamber being maintained at a pressure substantially less than atmospheric pressure;c) a means for maintaining a high electric potential difference between said liquid sample within the capillary means and said second wall, whereby the surface of said liquid sample is distorted at the outlet of said capillary means into a single electrospray cone-jet;d) a heating means for heating the liquid sample within the capillary means to prevent the freezing of electrospray cone-jet exiting said outlet of capillary means; ande) an aperture disposed in said second wall of said first chamber so that the liquid jet and any resulting highly charged droplets from the breakup of the liquid jet are emitted from said first chamber;and wherein said desolvation unit includes:f) a second chamber adjacent to said first chamber maintained at a pressure substantially less than atmospheric pressure and at a higher pressure than that of said first chamber, said second chamber includes said second wall of said first chamber, said aperture through which sample is emitted; and in which said liquid sample and analyte evaporate into a gas phase so that the analyte may be received by a detection device; andg) a heating means for heating said second chamber to facilitate the evaporation of said highly charged droplets.