Electrical field-flow fractionation using redox couple added to carrier fluid

A process for resolution and separation of particles in a test sample using an electrical field-flow fractionation channel through which a carrier fluid flows in a flow profile that is substantially parabolic generally throughout the channel, said process comprising;

• forming a thin flow channel having a top wall, a bottom wall, two side walls and an inlet end possessing an inlet means and an outlet end possessing an outlet means, with the top wall and bottom wall being spaced from each other by no more than about 200 microns;
• forming the inner surfaces of the top and bottom walls so that they are electrically conductive, whereby the inner surfaces of the top and bottom walls form electrodes as well as the opposite, broad boundary surfaces of said channel;
• applying a voltage differential to the electrodes forming the inner surfaces of the top and bottom walls of said channel;
• introducing the carrier fluid through said inlet means to flow through said channel and out of said outlet means, said carrier fluid comprising deionized or distilled water that contains a red-ox couple for carrying current in the carrier fluid in said channel;
• injecting the test sample into the carrier fluid flowing through the channel;
• and
• monitoring the carrier fluid at a downstream location from the injecting for particles from the test sample.