Electrophoretron: a new method for enhancing resolution in electrokinetic separations

Two capillaries, each of which have different surface preparations on their inside walls, are joined together to form a closed loop, and electrodes ar e placed inside the two capillaries. When the loop is filled with liquid an d a potential difference is applied between the two electrodes, a circulati ng flow of liquid is established inside the loop because the resistance to flow is unequal in going from one electrode to another in a clockwise versu s a counterclockwise direction. Consequently, a sample injected into this d evice, which we call an electrophoretron, repeatedly circulates between the two electrodes and the capillary separation column becomes effectively one of unlimited length. On each cycle the separation between analytes with di fferent mobilities increases, thus enhancing resolution of analytes having nearly the same mobilities. The operation of a prototype electrophoretron i s demonstrated. (C) 2001 Elsevier Science B.V. All rights reserved.