ION-EXCHANGE PRECONCENTRATION AND GROUP SEPARATION OF IONIC AND NEUTRAL ORGANIC-COMPOUNDS

In many cases sample pretreatment continues to be the most time-consuming and costly step in the analytical process. In the present work it is shown that macroporous ion-exchange resins of low exchange capacity can be used both to preconcentrate organic solutes from aqueous samples and to separate these solutes into groups. Thus, neutral and basic organic compounds are both taken up from aqueous solution by a very short column packed with a special cation-exchange resin. The neutral group of compounds is subsequently eluted with an organic solvent. The bases are then eluted by 2 M methylamine in methanol. In a similar manner organic acids are concentrated on a special anion-exchange column. Extensive data are shown to demonstrate the efficiency of the preconcentration and group separation of neutral and basic compounds.