FACTORS AFFECTING THE ION-CHROMATOGRAPHIC PRECONCENTRATION BEHAVIOR OF INORGANIC ANIONS AND ORGANIC-ACIDS

An ion chromatograph employing an IonPac AC10 concentrator column and AS10 analytical column with an hydroxide eluent was used to investigat e the preconcentration behaviour of inorganic anions and organic acids . Increased sample loading volumes resulted in decreased recoveries fo r weakly retained solutes, while the flow-rate at which the sample was loaded did not affect solute recovery, at least for flow-rates up to 5.0 ml/min. The recoveries obtained for weakly retained solutes were a lso influenced by the presence of sample matrix ions and the ion-excha nge selectivity of the concentrator column. Formate and chloride were found to modestly decrease the recovery of fluoride, while the presenc e of sulfate had a more significant impact. Sample matrix effects were minimized by using a concentrator column with an ion-exchange selecti vity that permits maximum retention of solutes, such as fluoride and f ormate, yet only moderate retention of anions, such as sulfate and oxa late. (C) 1997 Elsevier Science B.V.