Ananalytical separation of submicrometer colloid particles of different sizes is carried out through the open capillary tube emerging in order of decreasing diameter. The separation is caused mainly by the parabolic velocity profile in microcapillary tube. The rate of transport of the particles relative to eluant can be expressed in terms of the separation factor, which depends upon the particle size, tuve diameter, eluant ionic composition and the average velocity of the mobile phase. In this study, we used the fused-silica capillary tubes of 50㎛ and 75㎛ in diameter. We examined the mine various effects on the separation of collocidal particles such as the ratio of particle to tube diameter, eluant ionic composition, and eluant average velocity. In particular, we elucidated the electrokinetic effects of eluant ionic composition in terms of the ζ-potenitals of the particle and the capillary wall. Each ζ-potential was measured by a novel capillary electrophoresis apparatus, in which we employed the on-line UV detection to eliminate the dead volume effect by back mixing.
