Ion Exchange Chromatography

This is to separate ionic mixtures. The stationary phase of this technique is an ion-exchange resins where as the mobile phase is a buffered aqueous solution. Anions or cations can covalently attach onto the resin. The resin can be either cationic or anionic. Solute ions of the opposite charge in the mobile phase attach to the resin by electrostatic forces. Ion exchange columns are of two types. Those are cation exchange columns (contains negatively charged groups) and Anion exchange columns (contain positively charged groups). In here the charged analytes are attached to the counter ions (exchange groups) in the column. Analyte ions are eluted out using a buffer with a different pH (to weaken the electrostatic interactions between the analytes and the exchangers. Analytes are present in the mobile phase where as the exchange groups present in the column.