 Thus, polar solutes (such as acids and amines) are most strongly retained, with retention decreasing as the amount of water in the mobile phase increases.Typically the amount of the nonpolar component in the mobile phase must be 60% or greater with the exact point of increased retention depending on the solute and the organic component of the mobile phase.A true ANP stationary phase will be able to function in both the reversed phase and normal phase modes with only the amount of water in the eluent varying.