Flash chromatography- Flash chromatography is another term for “medium pressure chromatography. “ This particular method is a more efficient alternative to the more widely practiced gravity chromatography. It differs from gravity chromatography in that the silica particles are smaller, which makes it difficult for the solvent to travel. As a result, pressurized gas is used when conducting the column. Since the reaction is “over in a flash,” it has been named flash chromatography. ²