The Penn State Research Foundation

Beckman Instruments, Inc.

Mark A Hayes

Andrew G Ewing

Steven S Herrick

I Kheterpal

Indu Kheterpal

An electrophoretic separation apparatus includes a capillary tube having a length, a cross section, an inlet and an outlet. A first reservoir containing a solvent and, upon injection, a solute is in fluid-flow communication with the inlet and a second reservoir containing at least a solvent is also in fluid flow communication with the outlet, the capillary thereby being filled at least with the solvent. A first power supply applies a direct voltage separation potential between the first and second reservoirs and along the length of the capillary to thereby establish an electrophoretic flow of the solute therethrough. A second power supply applies an alternating voltage upon the direct voltage, and the DC impedance and AC impedance values are determined and subtracted to provide a direct measurement of the electroosmotic flow.

Real time monitoring of electroosmotic flow in capillary electrophoresis

An electrophoretic separation apparatus includes a capillary tube having a length, a cross section, an inlet and an outlet. A first reservoir containing a solvent and, upon injection, a solute is in fluid-flow communication with the inlet and a second reservoir containing at least a solvent is also in fluid flow communication with the outlet, the capillary thereby being filled at least with the solvent. A first power supply means applies a separation potential between the first and second reservoirs and along the length of the capillary to thereby establish an electrophoretic flow of the solute therethrough. An electrically isolated conductor is juxtaposed to an external surface of the capillary tube and is connected to a second power supply. An electrostatic field is thereby applied across the cross section of the capillary tube to control the electroosmotic flow therein. The electrical isolation of the conductor prevents current flow between the power supply and the conductor. The conductor achieves effective electroosmotic flow control even though it extends only over a small portion of the length of the capillary tube.

Capillary electrophoresis apparatus with improved electroosmotic flow

An electrophoretic separation apparatus includes a capillary tube having a length, a cross section, an inlet and an outlet. A first reservoir containing a solvent and, upon injection, a solute is in fluid-flow communication with the inlet and a second reservoir containing at least a solvent is also in fluid flow communication with the outlet, the capillary thereby being filled at least with the solvent. A first power supply means applies a separation potential between the first and second reservoirs and along the length of the capillary to thereby establish an electrophoretic flow of the solute therethrough. An electrically isolated plate is juxtaposed to an external surface of the capillary tube and is connected to a second power supply. An electrostatic field is thereby applied across the cross section of the capillary tube to control the electroosmotic flow therein. The electrical isolation of the plate prevents current flow between the power supply and the plate. The plate achieves effective electroosmotic flow control even though it extends only over a small portion of the length of the capillary tube.

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State College, PA, United States of America

Mark A Hayes