Chemical suppressors and method of use

Abstract

A non-electrolytic method and apparatus for treating an aqueous sample stream including analyte ions and matrix ions of opposite charge, for pretreatment or suppression. The apparatus includes an ion exchange membrane capable of passing only ions of opposite charge to the analyte ions, a sample stream flow channel, a first aqueous stream ion receiving flow channel adjacent one side of the sample stream flow channel and separated therefrom by the first ion exchange membrane, and stationary flow-through ion exchange packing disposed in the sample stream flow channel. The ion receiving channel has an ion exchange capacity for the matrix ions less than about 25% of the ion exchange capacity for the matrix ions.

1 . A non-electrolytic apparatus for treating an aqueous sample stream including analyte ions and matrix ions of opposite charge, said apparatus comprising a first ion exchange membrane capable of passing only ions of opposite charge to said analyte ions, a sample stream flow channel, a first aqueous stream ion receiving flow channel adjacent one side of said sample stream flow channel and separated therefrom by said first ion exchange membrane, stationary flow-through first packing of ion exchange material disposed in the sample stream flow channel of the same charge as said first membrane and having a first ion exchange capacity for said matrix ions, said first ion receiving channel having an ion exchange capacity for said matrix ions less than about 25% of said first ion exchange capacity for said matrix ions, said apparatus not including electrodes disposed to apply an electric field between said sample stream flow channel and said first ion receiving flow channel. 
   
   
       2 . The apparatus of  claim 1  further comprising a second ion exchange membrane of the same charge as said first ion exchange membrane, and a second aqueous stream ion receiving flow channel disposed adjacent the other side of said sample stream flow and separated therefrom by said second ion exchange membrane. 
   
   
       3 . The apparatus of  claim 1  in which said first ion receiving flow channel is substantially free of ion exchange capacity for said matrix ions. 
   
   
       4 . The apparatus of  claim 1  further comprising neutral flow-through packing in said first ion receiving flow channel. 
   
   
       5 . The apparatus of  claim 2  in which the second aqueous stream ion receiving flow channel has an ion exchange capacity for said matrix ions less than about 25% of said first ion exchange capacity for said matrix ions. 
   
   
       6 . The apparatus of  claim 1  in ion chromatography apparatus, further comprising a chromatography separator in fluid communication with the inlet of said sample stream flow channel and a detector for said analyte ions in fluid communication with the outlet of said sample flow channel. 
   
   
       7 . The apparatus of  claim 1  for treatment of a sample stream in combination with a chromatography apparatus, said apparatus further comprising a chromatography separator having an inlet and an outlet, said inlet being in fluid communication with said sample stream, and a detector in fluid communication with said chromatography separator. 
   
   
       8 . The apparatus of  claim 1  in which said first packing comprises a screen. 
   
   
       9 . A non-electrolytic apparatus for treating an aqueous sample stream including analyte ions and matrix ions of opposite charge, said apparatus comprising a first ion exchange membrane capable of passing only ions of opposite charge to said analyte ions, a sample stream flow channel, a first aqueous stream ion receiving flow channel adjacent one side of said sample stream flow channel and separated therefrom by said first ion exchange membrane, stationary flow-through first packing of ion exchange material disposed in the sample stream flow channel of the same charge as said first membrane and having a first ion exchange capacity for said matrix ions, said first ion receiving channel having second flow-through ion exchange packing of opposite charge to said first ion exchange packing disposed in said first ion receiving flow channel, said apparatus not including electrodes disposed to apply an electric field between said sample stream flow channel and said first ion receiving flow channel. 
   
   
       10 . A chromatography apparatus including apparatus for treating an aqueous sample stream including analyte ions and matrix ions of opposite charge, said apparatus comprising a chromatography separator having an inlet and an outlet, said inlet being in fluid communication with said sample stream, said treating apparatus being disposed upstream or downstream from said chromatography separator and comprising a first ion exchange membrane capable of passing only ions of opposite charge to said analyte ions, a sample stream flow channel, a first aqueous stream ion receiving flow channel adjacent one side of said sample stream flow channel and separated therefrom by said first ion exchange membrane, stationary flow-through first packing of ion exchange material disposed in the sample stream flow channel of the same charge as said first membrane and having a first ion exchange capacity for said matrix ions, said first ion receiving channel having an ion exchange capacity for said matrix ions less than about 25% of said first ion exchange capacity for said matrix ions. 
   
   
       11 . The chromatography apparatus of  claim 10  in which said treating apparatus further comprises a second ion exchange membrane of the same charge as said first ion exchange membrane, and a second aqueous stream ion receiving flow channel disposed adjacent the other side of said sample stream flow and separated therefrom by said second ion exchange membrane. 
   
   
       12 . The apparatus of  claim 10  in which said first ion receiving flow channel is substantially free of ion exchange capacity for said matrix ions. 
   
   
       13 . The apparatus of  claim 10  further comprising neutral flow-through packing in said first ion receiving flow channel. 
   
   
       14 . The apparatus of  claim 11  further comprising second flow-through ion exchange packing of opposite charge to said first ion exchange packing disposed in said first ion receiving flow channel. 
   
   
       15 . The apparatus of  claim 10  in ion chromatography apparatus, in which said chromatography separator is in fluid communication with the inlet of said sample stream flow channel. 
   
   
       16 . The apparatus of  claim 10  further comprising a detector in fluid communication with said chromatography suppressor. 
   
   
       17 . The apparatus of  claim 10  without electrodes for applying an electric field between said sample stream flow channel and first ion receiving flow channel. 
   
   
       18 . A chromatography method comprising flowing an aqueous sample stream including analyte ions of one charge and matrix ions of opposite charge to said analyte ions through a chromatography separator to separate the analyte ions, flowing the sample stream including the separated analyte ions through a sample stream flow channel, and simultaneously flowing an aqueous stream through an ion receiving flow channel separated therefrom by a first ion exchange membrane capable of passing only ions of opposite charge to said analyte ions and of blocking bulk liquid flow to reduce the concentration of said matrix ions in an effluent from said sample stream flow channel, said sample stream flow channel having stationary flow-through first packing of ion exchange material disposed in the sample stream flow channel of the same charge as said first membrane and having a first ion exchange capacity for said matrix ions, said ion receiving channel having an ion exchange capacity for said matrix ions less than about 25% of said first ion exchange capacity for said matrix ion. 
   
   
       19 . The method of  claim 18  in which said first ion receiving flow channel is substantially free of ion exchange capacity for said matrix ions. 
   
   
       20 . The method of  claim 18  in which second flow-through ion exchange packing of opposite charge to said first ion exchange packing is disposed in said first ion receiving flow channel. 
   
   
       21 . The method of  claim 18  further comprising detecting said separated analyte ions in the sample stream exiting from said sample stream flow channel. 
   
   
       22 . The method of  claim 18  in which an electric field is not applied between said sample stream flow channel and said first ion receiving flow channel.