B&M SAX is a strong anion exchange extraction column with silica gel, which has the quaternary ammonium salt functional group. Mainly used for the extraction of weak anionic compounds, such as carboxylic acid. The strong anion exchanger can be used to extract the negative charge from water and non-aqueous solution, especially for the extraction of weak acid. It is often used to remove the strong anions (organic acids, nucleotides, nucleic acids, sulfonic acid roots, inorganic salts, etc.) in the sample, and the biological macromolecule desalination.