Simultaneous determination of inorganic anions and metal ions by suppressed ion chromatography

Abstract

In this work the simultaneous determination of environmentally interesting inorganic anions (BrO − 3, SeO 2− 3, SeO 2− 4, HAsO 2− 4, WO 2− 4, MoO 2− 4, CrO 2− 4) and metal ions (Pb 2+, Cd 2+, Ni 2+, Cu 2+) precomplexed by EDTA by suppressed ion chromatography has been optimized. Throughout the work, a latex-based strong anion-exchange resin and carbonate buffer as eluent have been used. The study was performed in presence of anions that commonly occur in real samples (Cl −, NO − 3, SO 2− 4). Separation has been optimized studying the main eluent parameters that influence analyte retention, that is carbonate concentration and pH. The method developed has been applied to the determination of the species present in a water sample of the river Po (Turin, Italy). In order to reduce analysis time, the effect of carbonate concentration and pH gradient elutions have been studied. The gradient elution allowed us shorter chromatographic runs without the baseline drift that usually arises during gradient elutions.