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

• Flow segmentation can be used to measure radial dispersion coefficient (D rad) in practice. • Mass flow meter feedback can be used to correct flow rate mismatches. • Method validated by showing independence of relative central flow rate and tracer concentration. • Measured D rad -values higher than in most engineering literature reports but still within cited range. 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 D eff for 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 ν, a quasi-linear relationship is obtained. The slope of the curve (β = 0.38 and β = 0.46 for toluene and acetophenone, respectively) is significantly larger than the value that is most frequently cited in engineering literature. However, the obtained β-values and D rad /D mol -values still fall within the broad range of β- and D rad /D mol -values cited in literature. [ABSTRACT FROM AUTHOR]