Flash Chromatography is a method of separating and purifying a product by running it through a column filled with Silica gel and an eluting solvent.  Flash chromatography differs from the conventional method of chromatography because it uses smaller silica gel particles and pressurized air to push the solvent through the column, resulting in a much faster process. A solvent should be used that gives the product a TLC Rf of .15-.2, and binary solvent systems are often used.  As the solvent is run through the column, fractions are collected and tested by TLC for the presence of the product.  All fractions which contain the product are combined..