How does reverse-phase chromatography separate proteins?

In reversed-phase chromatography, silica that is chemically modified with hydrophobic groups is used as the stationary phase. The stationary surface retains proteins by the adsorption of the protein’s hydrophobic domains. When the mobile phase reaches a specific concentration of organic solvent, the protein desorbs from the surface and elutes from the column. The concentration of organic solvent required to desorb the protein is a function of the hydrophobic domain’s size, which is highly specific; thereby different proteins can be eluted by adjusting the concentration of organic solvent.