Van Deemter equation

The Van Deemter equation describes how efficiently a column separates substances in chromatography by showing how different factors affect the speed and quality of the separation. It considers three main effects: longitudinal diffusion (spread of molecules along the column), only allowing narrow bands of substances to exit at the right time; multiple paths the molecules can take (mass transfer resistance), which can slow down the process; and the flow rate of the mobile phase (carrier liquid or gas). The goal is to find the optimal flow rate where these effects balance out, maximizing resolution and speed of separation.