Work out extraction partition coefficient instantly with clear inputs, formula shown and shareable results.
The partition coefficient is the ratio of equilibrium concentrations in the two phases and is a property of the solute and solvent pair. How much actually transfers also depends on the volumes: the fraction extracted is KdVo/(KdVo + Va). With Kd = 4 and equal volumes, 80% moves across in one contact, which is why two small washes beat one large one.
Partition coefficient
Kd = [solute in organic] / [solute in aqueous]
Fraction extracted
fraction = Kd.Vo / (Kd.Vo + Va)
Each contact removes the same fraction of what remains, so repeating compounds the recovery. Three 20 mL washes beat one 60 mL wash at the same Kd.
The base-ten log of the partition coefficient, usually for octanol-water. It is the standard lipophilicity measure in drug design.