In 1964, University of Utah chemistry professor J. Calvin Giddings enunciated a theoretical platform, “unified separation science,” that could confer the resolving power of GC to LC. Giddings’ model combined the higher mobile phase diffusion and efficiency of GC with LC’s higher selectivity via orthogonal separation modes. His vision has been made a reality through supercritical fluid chromatography (SFC), which uses supercritical or subcritical carbon dioxide as the mobile phase.