Author: David S. Bell
Published By: Journal of Chromatography A
Year of Publication: December 2018
Volume, Issue:Volumes 1581–1582
We report on a systematic study involving columns with a clearly different efficiency (4 distinct quality groups) obtained by packing the columns that were C18 bonded and end capped with a different carbon loading. Using B-term analysis (via peak parking) and theoretical models to estimate the magnitude of the Cm– and Cs-term contributions, it could be concluded that the difference in efficiency among the groups was entirely due to a difference in eddy dispersion. As such, the columns provided an ideal testing ground to verify how well the total pore blocking (TPB)-method can be used to probe differences in packing heterogeneity. In agreement with earlier literature observations, it turns out the TPB-method is much more sensitive to packing heterogeneities than the eddy dispersion (Heddy)-contribution measured under open-pore conditions via B- and C- term subtraction. Typically, differences in Heddy on the order of 0.1–0.5μm translate into a difference on the order of 0.5–2μm in the TPB mode. This confirms the TPB as a powerful technique to make very sensitive measurements of the homogeneity of packed beds.