title: Taylor dispersion in equilibrium gradient focusing at steady state.
abstract: An analytic expression is presented for the effective dispersion coefficient in the case where a solute is focused in a parabolic flow against a linear gradient in a restoring force. This expression was derived by employing a minor variation on the method of moments used by Aris in his development of the dispersion coefficients for a time-dependent, isocratic system. In the present case, dispersion is controlled by two dimensionless groups, a Peclet number which is proportional to the parabolic component of the flow, and a gradient number which is proportional to the slope of the restoring force. These results confirm that the Aris-Taylor expression for the dispersion coefficient should not be applied in cases where a solute is focused to a stationary steady state.
authors.affiliation: Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
authors.forename: Cornelius F
authors.initials: CF
authors.lastname: Ivory
mesh_terms: D053841:Electroosmosis / Q000379:methods*; D004586:Electrophoresis / Q000379:methods*; D008956:Models, Chemical; D012996:Solutions / Q000737:chemistry
chemical_list: D012996:Solutions
keywords: Aris-Taylor dispersion; Dispersion; Electrofocusing; Equilibrium gradient methods; Steady state