DR wrote:
Capacity is limited by column geometry, but at what point is strictly a function of the partition coefficient...
capacity of the column depends on the chemistry to much higher degree than column dimensions. In mixed-mode chromatography if have capacity which is 5-20 times higher than RP column. This also allows you to have a mismatch between diluent and mobile phase as well as the presence of salts in the sample and inject larger volumes. I just finished the study for bunch of columns for the analysis of the drug vildagliptin and compared Amaze SC mixed-mode column to leading brands RP column. Efficiency is twice higher on Amaze SC and peak shape is way better (1.5 in current gradient method vs. symmetry of 0.95-1 with isocratic methods on Amaze SC) for the same size particles, it also let inject compound in water (or high organic) and still not observe a peak disturbance on 50 uL injections.
This study is available upon request through our website.