Abstract: This free flow electrophoresis separation apparatus includes means for controlling the buffer flow across the separation chamber. This is useful in controlling crescent distortion of the sample streams as well as minimizing undesired pressure differentials within the apparatus. The electrophoresis separation apparatus is constructed such that two buffer flow paths are provided. The first flow path connects the outlet of the first electrode chamber with the inlet of the second inlet chamber, and the second flow path connects the outlet of the second electrode chamber with the inlet of the first electrode chamber. Each flow path is driven by separate pump means.