Peak shape and dispersion behavior of solutes in counter-current chromatography with a single phase

The dispersion behavior of solutes was investigated in a rotating flowing coiled tube. Potassium iodide, tartrazine, ascorbic acid, lysozyme, bovine serum albumin (BSA), and silver nanoparticle (AgNPs) samples were eluted in a coiled tube of counter-current chromatography (CCC) apparatus with a single phase. Apparent convection peaks of low-diffusivity solutes appeared in the static CCC tube, while Gaussian-like peaks showed up for the high-diffusivity solutes. When the rotation speed of the CCC apparatus was elevated, all solute peak widths became smaller, and the convection peaks of AgNPs and BSA were minimized and formed Gaussian-like peaks. The axial dispersions of all solutes were reduced owing to the higher radial mass transfer in the rotating CCC column. The same reasoning could also be used to rationalize other special band shapes encountered in two-phase CCC separations.