Keq[C]. For industrial scale uses, the total binding molecules on the column resin beads must be factored in because unoccupied sites must be taken into account. The Langmuir isotherm and Freundlich isotherm are useful in describing this equilibrium. Langmuir Isotherm: [CS] = (KeqStot[C])/(1 + Keq[C]), where Stot is the total binding molecules on the beads. Freundlich isotherm: [CS] = Keq[C]1/n The Freundlich isotherm is used when the column can bind to many different samples in the solution that needs to be purified. Because the many different samples have different binding constants to the beads, there are many different Keqs. Therefore, the Langmuir isotherm is not a good model for binding in this case. See also High performance liquid chromatography (HPLC) for column chromatography using high pressure. Fast protein liquid chromatography (FPLC) for separation of proteins using column chromatography. References External links Flash Column Chromatography Guide (pdf) Radial Flow Chromatography Chromatography Laboratory techniques