Fluorescent dyes mobility measurement

This project investigates a new technique to measure ionic mobility of fluorescent dyes, which is based on the formation of alternate fluid crescents under time-periodic electroosmotic flow through a constriction. The movements of the fluorescent fluid crescents were captured with a charged couple device (CCD) camera and their velocities were measured. The ionic mobility of the dye was then calculated, by taking into account the electroosmotic flow velocity. It has been shown that, for this method, conductivity matching between the fluorescent and non-fluorescent buffer solution is critical to obtain valid results of ionic mobility value. The consistency of the crescent velocity measurement was improved by introducing a DC voltage bias difference between the two inlets, due to sharper crescent formation and intensity profile. Joule heating due to high conductivity of buffer solutions was one of the issues which affected the results.Bachelor of Engineering (Mechanical Engineering