2.5.2 Flash Chromatography and Preparative HPLC

Flash chromatography accelerates the classical gravity-column workflow through applied air or nitrogen pressure, commonly using reversed-phase C18 silica...

Flash chromatography accelerates the classical gravity-column workflow through applied air or nitrogen pressure, commonly using reversed-phase C18 silica with an aqueous-organic gradient, and is considerably faster than traditional open-column chromatography while remaining suitable for gram-scale purification. Preparative and semi-preparative HPLC, using wide-bore (10–20 mm internal diameter) C18 columns loaded with tens to hundreds of milligrams of a pre-fractionated sample per injection, provides the final purification step required to achieve the greater than 95% purity typically demanded before a compound is submitted for detailed spectroscopic structure elucidation or biological testing, with fraction collection guided by real-time ultraviolet detection at 254 or 280 nm.