The Dionex IonPac CTC-1 and Dionex IonPac CTC 500 Cation Trap Columns contain microporous cation-exchange resin in the hydronium form. The cation trap columns strip trace cationic contaminants out of the eluent and/or deionized water and prevents them from reaching the guard or analytical columns. Cationic contaminants present on the eluent and/or deionized water often interfere with the precision of trace cation determinations in particular when performing an cation-exchange application that involves a gradient eluent.