Electrokinetic devices and methods are described with the purpose of collecting assayable agents from a dielectric fluid medium. The computer program product and method includes the steps of identifying a solution for preparation and its associated volume. The gain circuit is connected to receive the output from the transconductance circuit, wherein the gain circuit includes a transistor that is matched to the second transistor of the H-bridge. A charge blocking layer is formed over the tunnel insulator. Tracking circuitry is connected to the device and remains in communication with the first bus transmission medium. Between successive elution runs, at least one performance parameter of the elution system is adjusted based on the accumulated error data.