Determination of the intraparticle electroosmotic volumetric flow-rate, velocity and Peclet number in capillary electrochromatography from pore network theory

The results obtained from the pore network model employed in this work, cle arly show that the magnitudes of the intraparticle electroosmotic volumetri c flow-rate, Q(intrap) and velocity, (nu(intrap,x)), in the pores of the ch arged porous silica particles considered in this study are greater than zer o. The intraparticle Peclet number, Pe(intrap), of a solute in these charge d porous silica particles would be greater than zero, and, in fact, the mag nitude of the intraparticle Peclet number, Pe(intrap), of lysozyme is great er than unity for all the values of the pore connectivity, n(T), of the int raparticle pores and of the applied electric potential difference per unit length, E-x, dong the axis of the capillary column considered in this work. Furthermore, the values of the intraparticle electroosmotic volumetric flo w-rate, Q(intrap) and velocity, (nu(intrap,x)), as well as the magnitude of the pore diffusion coefficient, D-p, of the solute increase as the value o f the pore connectivity, n(T), of the intraparticle pores increases. The in traparticle electroosmotic flow can contribute significantly, if the approp riate chemistry is employed in the mobile liquid phase and in the charged p orous particles, in (i) decreasing the intraparticle mass transfer resistan ce, (ii) decreasing the dispersive mass transfer effects, and (iii) increas ing the intraparticle mass transfer rates so that high column efficiency an d resolution can be obtained. (C) 2000 Elsevier Science B.V. All rights res erved.