The Nucleosil 5SA - 125/4.0 IC cation column uses sulfonic acid groups for separating cations. With eluents containing organic acids and ethylenediamine, this column separates divalent cations such as magnesium and calcium as well as several transition metal elements (e.g., nickel, zinc, cobalt, manganese). The Nucleosil 5SA - 125/4.0 is therefore the inexpensive and robust separation column for the determination of transition metals by direct conductivity measurement without post-column reaction. In addition to high concentrations of alkaline metals, calcium and magnesium can be determined reliably. The column is suitable only for divalent cations. Monovalent cations elute practically simultaneously with the injection peak.