Alternative method to study the radial dispersion in liquid chromatography columns. Part II: Experimental

The present contribution reports on the practical implementation and validation of a new experimental method to determine the radial dispersion (D-rad) in packed bed liquid chromatography columns, as well as on the results obtained with it. A first important validation was that the measured D-rad-values were independent of the applied relative central flow rate (varied from 25% to 57%). The obtained D-rad-values did not vary significantly when changing the concentration of the injected tracer to check potential mass overloading effects (25, 50 or 75 ppm of tracer for the acetophenone measurements; 12.5 and 25 ppm of tracer for the toluene measurements). And yet another important validation step was the observation that the D-rad-values clearly converged to the value of Defffor velocities going to zero, as physically and theoretically expected.

Plotting the obtained results as a plot of D-rad/D-mol versus the reduced velocity nu, a quasi-linear relationship is obtained. The slope of the curve (beta = 0.38 and beta = 0.46 for toluene and acetophenone, respectively) is significantly larger than the value that is most frequently cited in engineering literature. However, the obtained beta-values and D-rad/D-mol-values still fall within the broad range of beta- and D-rad/D-mol values cited in literature. (C) 2020 Elsevier B.V. All rights reserved.

Publication year:2020

Keywords:Radial dispersion drad, Flow segmentation, Packed bed column

CSS-citation score:1

Accessibility:Open