THE MAGNITUDE AND REPRODUCIBILITY OF THE ELECTROOSMOTIC FLOW IN SILICA CAPILLARY TUBES

The influence of a number of factors, such as the nature of the buffer , the presence of additives therein, the manufacturing conditions, and the pretreatment of the capillary, on the magnitude and repeatability of the electroosmotic flow (EOF) in silica capillary tubes has been i nvestigated. It was established that the nature of the buffer plays th e most significant role in respect of the stability and magnitude of E OF, whereas the conditions used for manufacture and pretreatment of th e tubing are less important. The EOF obtained using buffers consisting of tris(hydroxymethyl)aminomethane and ethylenediamine was more repea table than that obtained using pure phosphate buffers. Buffer additive s such as sodium dodecylsulfate, 1-butanol, sodium salts of 1-pentanes ulfonic acid and 1-heptanesulfonic acid, altered the magnitude of the EOF only, not its repeatability.