(96g) Microchannel Separations Using Oscillating Flow

This research expands upon separation techniques developed for use in microchannels, also known as microreactors or microfluidic chips. It is proposed that the use of oscillating flow enhances the ability to separate multi-component samples, including biological samples such as DNA or proteins. This research, however, is preliminary to any testing that would use biological samples. In stead, a mixture of two fluorescent dyes, Rhodamine B and Fluorescein, were used as the sample, while de-ionized water with a pH of 10 was used as the medium. The microchannels are t-shaped and made of glass. There are two perpendicular channels that cross with one channel longer than the other. The cross section of the channel is semi-circular with a radius of 25 microns. Electrodes were placed at the ends of the longer channel and an offset alternating current was imposed along the channel. This current at 400 volts produced an Electrophoretic oscillating flow within the channel. The dyes were transported down the long channel and their relative movement was then observed. The two different species developed unique regions of high concentration in the channel that were seen under a microscope. The flow oscillations transported one species differently than the other indicating that separation could be possible by using a form of this method.