Analytical Sciences

Kinetic Study of the Concentration Dependence of the Mass Transfer Rate Coefficient in Enantiomeric Separation on a Polymeric Imprinted Stationary Phase

Kanji MIYABE and Georges GUIOCHON  

Department of Chemistry, The University of Tennessee, Knoxville, TN 37996-1600 USA and Division of Chemical and Analytical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

Kinetic data previously acquired on the enantiomeric separation of L- and D-phenylalanine anilide (PA) on a polymeric stationary phase imprinted with L-PA were reinterpreted. The parameters characterizing the mass transport processes active in the column, i.e., axial dispersion, fluid-to-particle mass transfer, intraparticle diffusion, and adsorption/desorption were calculated. Intraparticle diffusion was shown to have a dominant contribution to band broadening. The surface diffusion coefficient (D_s) showed a positive concentration dependence which could explain the dependence of the lumped mass transfer rate coefficient on the enantiomer concentration. It is likely that the positive concentration dependence of D_s could be explained by the heterogeneity of the surface of the stationary phase and that the distribution of adsorption energy on the surface of the imprinted polymer has an exponential decay profile.

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