Apparatus for electrokinetic fractionation (A) Apparatus configuration of the anode-side. The apparatus on the cathode-side is image-symmetric to that on the anode-side. DM, dialysis membrane; DMI, dialysis membrane interface. Separation capillary, 45 cm coated capillary with an o.d. of 360 μm and an i.d. of 150 μm; Teflon tubing, 22 cm with an o.d. of 1.05 mm and an i.d. of 0.55 mm; anode/cathode reservoir, 100 mL container; anode/cathode collection reservoir, 600 μL tube. (B) Preparation of DMI. (Reprinted from reference57 with permission)