Nonlinear liquid-liquid chromatography: Beyond a constant distribution coefficient

•The first systematic study of liquid-liquid chromatography (LLC) in the nonlinear range of the distribution isotherm.•Pulse injection experiments with cannabidiol (CBD, 1–300 mg/mL) were performed in three units of different designs and volumes (20 mL-2 L).•At higher concentrations, the CBD elution profiles showed a diffusive front and sharp rear part.•The elution profiles were successfully simulated with the equilibrium-cell model and a nonlinear correlation describing the CBD distribution isotherm.•The distribution isotherm parameters were determined by the peak fitting method.