Ion-Chromatography performance of Poly(Aspartic) Acid Bonded Silica with various pore sizes at different ionic strengths and column temperatures

Abstract

A significant effect of pore size on selectivity was observed for anion exchange on polyaspartic acid-coated silica (PolyCAT A). The retention order of halogenide anions, Cl– <Br– <I–, was completely reversed between 30nm and 6nm pore materials. The zwitterionic nature of PolyCAT A made possible the simultaneous separation of anions and cations. With the column temperature, retention of cations is increased whereas retention of anions is decreased. The ionic composition of the eluent had a dramatic effect on separation efficiency with PolyCAT A of 30nm pores. The separation efficiency of ions was optimal in sulfuric acid-based eluents of reasonably high ionic strength.