Retention and separation of inorganic anions by reversed-phase ion-interaction chromatography on octadecyl silica

Abstract

The retention behaviour of chloride, nitrite, bromide, nitrate and sulphate was investigated using Partisil 10 ODS-3 as the stationary phase and a solution of tetrabutylammonium in aqueuos phthalate or phosphate buffer as the eluent. The quaternary ammonium ion adsorption behaviour and the influence of the quatenary ammonium concentration, the pH and the buffer concentration on the retention of the inorganic anions is discussed. The major adsorption and ion-exchange equilibria in the retention process were studied and used to develop a retention model for the different analytes. This retention model was verified experimentally. Ion-interaction reversed-phase chromatography with an octadecyl-bonded silica stationary phase and tetrabutylammonium iodide—phthalate eluent was found to be successful system for the separation and determination of inorganic anions and when conductivity detection is used.