Based on the local equilibrium assumption in non-equilibrium thermodynamic separation theory (NTST) and Lagrangian description in hydrodynamics, state recursion equations (SRE) concerning zone migration and spreading were obtained. It overcomes the limits of plate theory which fails in accurate predicting zone spreading of the linear column chromatography separation systems with time-varying operation parameters. The experimental data of reversed-phase gradient- elution liquid chromatography support the theoretical predictions with SRE. It is more accurate to predict the zone spreading with SRE than predictions with plate theory in time-varying external force fields. The discovery of SRE lays a foundation of multistage-control and dynamic optimization of column separation with NTST.

Key words: COLUMN CHROMATOGRAPHY, ISOLATION, SOLUTE, DIFFUSION