SIZE-EXCLUSION CHROMATOGRAPHY OF CARBOXYL-TERMINATED DENDRIMERS AS A MODEL FOR PERMEATION OF CHARGED-PARTICLES INTO LIKE-CHARGED CAVITIES

In order to examine the permeation of small charged colloids into cavi ties of like charge, size-exclusion chromatography was carried out wit h carboxyl-terminated dendritic polymers on a porous glass stationary phase. Chromatographic partition coefficients K-SEC were measured for solute diameters ranging from 2 to 8 mn, at neutral pH, and ionic stre ngths from 0.01 to 0.09 M, and were reported relative to those of noni nteracting solutes of equal size (pullulan and Ficoll). The experiment al results were compared to values calculated using the treatment of F . G. Smith III and W. M. Deen for charged spheres in cylindrical pores of like charge (J. Colloid Interface Sci. 78, 44 (1980); 91, 571 (198 3)). The measured degrees of permeation were typically 20-100% larger than the calculated values, the discrepancies being greatest for the l arger solutes at high ionic strength. It is shown that the tendency of the calculations to overestimate the repulsion are likely to arise fr om linearization of the Poisson-Boltzmann equation. (C) 1996 Academic Press, Inc.