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Ion Exchange Columns

Silica Based IEX Columns | USP® L9 Class | Chosen for Polar Compound Purification



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Ion exchange chromatography is the most popular method for the purification and analysis of charged molecules. (IEX) HPLC is the separation of polar (charged) molecules including and not limited to amino acids, proteins, peptides, organic acids and bases, based on their affinity to ionic groups bonded on the silica. The retention on the column is reversible through the "exchange" of ions between the target ions in the mobile phase and the ions present on the ligands. Use acids in basic mobile phases and bases in acidic mobile phases.



Cation Exchange Columns have a negatively charged ionic group with an affinity for polar molecules with positive charges. Use to retain bases.


Anion Exchange Columns have a positive charged ionic group with an affinity for polar molecules having a negative charge. Use to retain acids.


"Strong and Weak" Ion Exchange is not related to the strength of ion retention or binding. It refers to the range that ionization or non-ionization of the functional groups will vary with the pH of the mobile phase. A "Weak Ion Exchange" phase is ionized over a pH range, while a “strong” Exchange phase shows no variation in ionization at any pH. The Strong Exchangers are always ionized irrespective of pH.


  • Cogent IEX SAX™ - Strong Anion Exchange HPLC Columns have Quaternary Amine functional groups bonded to our Cogent RP™ world class 5 or 10um, 100A silica. Functional pH range 2.5-8.
  • Cogent IEX SCX™ - Strong Cation Exchange HPLC Columns have Sulfonic Acid groups bonded to our Cogent RP™ world class 5 or 10um, 100A silica. Functional pH range 2.5 -8.
  • Cogent IEX WAX™ - Weak Anion Exchange HPLC Columns have Diethylaminopropyl groups bonded to our Cogent RP™ world class 5 or 10um, 100A silica. Functional pH range 5 - 8.
  • Cogent IEX WCX™ - Weak Cation Exchange HPLC Columns have carboxylic acid groups bonded to our Cogent RP™ world class 5 or 10um, 100A silica. Functional pH range 2.5-7.