title: A method for determining electrophoretic and electroosmotic mobilities using AC and DC electric field particle displacements.
abstract: We have developed a method for measuring the electrophoretic mobility of submicrometer, fluorescently labeled particles and the electroosmotic mobility of a microchannel. We derive explicit expressions for the unknown electrophoretic and the electroosmotic mobilities as a function of particle displacements resulting from alternating current (AC) and direct current (DC) applied electric fields. Images of particle displacements are captured using an epifluorescent microscope and a CCD camera. A custom image-processing code was developed to determine image streak lengths associated with AC measurements, and a custom particle tracking velocimetry (PTV) code was devised to determine DC particle displacements. Statistical analysis was applied to relate mobility estimates to measured particle displacement distributions.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA. oddy@stanford.edu
authors.forename: M H
authors.initials: MH
authors.lastname: Oddy
authors.forename: J G
authors.initials: JG
authors.lastname: Santiago