Patent ID: 7982185
Filing Date: 2011-07-19
Classification: H01J

Abstract:
1. An apparatus for ionizing chemical species comprising: an Atmospheric Pressure Chemical Ionization inlet probe and ion source comprising a sample solution nebulizer, a heater to vaporize the nebulized sample solution, a vapor flow channel comprising a corona discharge needle with a tip surrounded by at least one counter electrode shaped to partially shield a corona discharge electric field and to allow penetration of external electric fields into an exit end of said vapor flow channel, said vapor flow channel comprising walls, an endplate electrode with voltage, and means to apply voltage to said corona discharge needle, said at least one counter electrode and said endplate electrode form a corona discharge at said tip and provide an electric field penetrating into said vapor flow channel to focus direct Atmospheric Pressure Chemical Ionization generated ions away from the walls of said vapor flow channel.