Patent ID: 7517696

Claim:
A non-electrolytic method for treating an aqueous sample stream including analyte ions of one charge and matrix ions of opposite charge to said analyte ions, said method comprising flowing the sample stream through a sample stream flow channel, 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 a second flow-through exchange packing of opposite charge to said first ion exchange packing disposed therein, an electric field not being applied between said sample stream flow channel and said first ion receiving flow channel.