PREDICTION OF RETENTION FOR HALIDE ANIONS AND OXOANIONS IN SUPPRESSEDION CHROMATOGRAPHY USING MULTIPLE SPECIES FLUENT

The retention behavior of inorganic halide and oxoanions is studied as a function of changing eluent composition. The model developed for se paration of Cl-, Br-, ClO3-, BrO3-, SeO32-, SeO42-, and PO43- ions wit h eluent containing HCO3-, CO32-, and OH- anions is utilized for deter mination of selectivity coefficients for sample and eluent species. It can also take into account the protonation of the sample ions. The mo del effectively characterizes the behavior of the analytes under eluti on conditions of practical importance. The predicted and measured rete ntions are in rather good agreement. The capacity factors determined f or these anions make possible a reliable planning for IC separation of them with carbonate eluent in relatively wide ranges of concentration and pH. The different retention behaviors of mono-, di-, and trivalen t anions as a function of pH are also interpreted in this eluent syste m.