High-speed simultaneous ion-exclusion/cation-exchange chromatography of anions and cations on a weakly acidic cation-exchange resin column

Abstract

The simultaneous ion-exclusion/cation-exchange separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin of 3 μm particle size was used to achieve the simultaneous high-speed separation of anions and cations (Cl −, NO 3 −, SO 4 2−, Na +, K +, NH 4 +, Ca 2+ and Mg 2+) commonly found in environmental samples. The high-speed simultaneous separation is based on a combination of the ion-exclusion mechanism for the anions and the cation-exchange mechanism for cations. The complete separation of the anions and cations was achieved in 5 min by elution with 15 m M tartaric acid–2.5 m M 18-crown-6 at a flow-rate of 1.5 ml/min. Detection limits at S/ N=3 ranged from 0.36 to 0.68 μ M for anions and 0.63–0.99 μ M for cations. This method has been applied to the simultaneous determination of anions and cations in several environmental waters with satisfactory results.