 In both cases, the work of gravity is allowed influence the two immiscible liquids of different densities to form the signature droplets that rise or descend through the column.The mobile phase is pumped at a rate that will allow droplets to form that maximize the mass transfer of a compound between the upper and lower phases.Compounds that are more soluble in the upper phase will travel quickly through the column, while compounds that are more soluble in the stationary phase will linger.