Knowing when it is time to replace your reversed-phase flash column is a question I am asked frequently along with…

Flash chromatography is the most commonly used purification tool for organic and medicinal chemists whose reaction scales typically range from milligrams to grams. The column size to be used for the purification of these reaction mixtures is selected either by using the 1% rule which states that for many reaction mixtures, a crude reaction mixture load equaling 1% of the column’s media weight often will provide the needed purity, assuming the right elution method is selected. While this strategy can work, often chemists either overload or underload the selected column resulting in low product purity which requires re-purification. In both situations, the chemists wastes time, solvent, and the cost of the column.