Fast and Simple method for Determining the Amount of Anion Exchange Groups on Resins

Ion exchange chromatography is one of the most commonly used techniques for the purification and separation of polar samples such as minerals in water or charged biomolecules (Figure 1).

The technique is based upon reversible binding of the charged species to an oppositely charged group that is attached to an insoluble matrix. A quantitative measure of an ion exchanger’s ability to take up exchangeable counter-ions is its capacity, which strongly influence support properties and can be measured by potentiometric titration with a strong acid or base [2]. However, the time to achieve the ion exchange equilibrium (the stationary state the potentiometric titration is based upon) is very long [3]. Consequently, a new method to measure the total ionic capacity of anion exchange resins is being developed.