Patent ID: 7029561

Claim:
A method for directing ionic analytes contained in an ionic buffer solution, said ionic buffer solution having a temperature dependent property selected from the group consisting of ionic strength and pH, said method comprising the steps of: applying an electric field to an ionic buffer solution containing at least one species of ionic analyte to cause the analyte ions to have electrophoretic motion; establishing, in said buffer solution, a temperature gradient having a significant component substantially aligned with the electrophoretic motion of the analyte ions, which produces a gradient in the ionic strength or pH of said buffer solution, thereby generating a gradient of the electrophoretic velocity of the analytes; and producing a bulk flow of said buffer solution to have a significant component substantially aligned in the direction opposite the direction of the electrophoretic motion of one or more of the analytes so that at least one of said one or more analytes will accumulate or be focused at at least one point along said temperature gradient, the pH at said at least one point being unequal to the isoelectric point of said at least one of said one or more analytes that are focused at said at least one point.