An exactly solvable Ogston model of gel electrophoresis V. Attractive gel-analyte interactions and their effects on the Ferguson plot

We examine the effect of attractive analyte-gel interactions within the fra mework of our recently developed lattice model of gel electrophoresis. We s how that it is possible to take into account such interactions and still ca lculate exact mobilities for various analytes and gel structures. Our study then focuses on two main issues: (i) the effect of these interactions on t he separation efficiency of the Ogston regime; and (ii) the presence of inf lection points (changes of curvature) in Ferguson plots. We establish some general principles, and we describe the results for selected two- and three -dimensional model systems. Numerous practical problems, such as chiral sep arations and affinity electrophoresis, can be treated using this approach.