Selectivity of chemically bonded zwitterion-exchange stationary phases in ion chromatography

P.N. Nesterenko, A.I. Elefterov, D.A. Tarasenko, O.A. Shpigun

J.Chromatogr., v. 706(1+2). p. 59-68 (1995)

ABSTRACT. A number of zwitterion-exchange stationary phases were prepared by immobilization of amino acids of different structure (Asp, Glu, Val, Tyr, Pro, Hypro, Arg, and Lys) on a silica surface. The occurrence of oppositely charged groups in a single ion-exchange site provided cation-, anion- and zwitterion-exchange properties. The chromatographic behaviour of these stationary phases was evaluated by the retenrion of a series of test organic compounds of different ionogenic nature. The role of the type and structure of the ion-exchange site was considered. The structure of the bonded molecules and the pH of the eluent were shown to be key parameters influencing the ion-exchange properties of amino acid-bonded silicas. The cation-exchange selectivity of phase containing primary or secondary amino groups was investigated for retention of alkali and alkaline earth metal ions. The application of amino acid-bonded silicas to the ion chromatographic separation of anions and cations is described.

Laboratory of Chromatography