The innovative substrate on a polyvinyl alcohol base increases selectivity for monovalent and divalent cations significantly. A characteristic of this is the number of "theoretical plates per meter". On the Metrosep C 3 - 250/4.0, for example, 42,000 plates are achieved for sodium, 51,000 for ammonium, and 31,000 for barium with its delayed elution. The peak forms on this cation column are highly symmetrical.
The selectivity of the Metrosep C 3 - 250/4.0 also permits the separation of transition metals. Because Metrohm ion chromatographs generally determine the cations without chemical suppression, the transition metals can be analyzed on the Metrosep C 3 - 250/4.0 together with the alkaline and earth alkaline metals.