Abstract: A method and apparatus is described for separating materials on the basis of differences in isoelectric points. In one aspect of the invention an electrochemical cell is provided which has a cell compartment having a plurality of interwaterproof compartments. Provided is a cell lid with a plurality of parallel panels which are narrower than the interwaterproof compartments. A pair of spaced electrodes are attached to the lid and insertable into the end compartments. When the lid is placed on the cell, with an appropriate amount of solution in the cell, a convection free current flow path is formed through the solution above the top edges of the compartments and along the sides of the cell between the gaps formed between the cell side walls and the edges of the narrower lid panels. A natural pH gradient is established when material containing the substance to be separated is dissolved in an appropriate solvent, thereby eliminating the need for expensive carrier ampholytes.