Silicas modified by polyelectrolyte complexes for the ion chromatography of anionic complexes of transition metals.

A.V. Pirogov, N.V. Svintsova, O.V. Kuzina, O.V. Krokhin, M.M. Platonov, O.A. Shpigun

Fresenius J.Anal.Chem., v.361, p.288-293 (1998)

ABSTRACT. An approach, which is based on the fact that an anionic-exchange layer may be bound at the surface of a cation-exchanger by electrostatic interaction of reversibly-charged functional groups, was used for producing polyelectrolyte anion-exchangers. Water-soluble polymers containing positively charged nitrogen atoms were used instead of anion-exchanging latex utilised in synthesising pellicular sorbents. Sulfonated co-polymer of styrene and divinylbenzene was replaced with a sorbent for reversed-phase chromatography (silica coated with dodecylbenzenesulfonic acid). The ion-chromatographic behaviour of transition metals complexes with ethylenediaminetetraacetic acid (EDTA), and cyclohexanediaminetetraacetic acid (CDTA) separated on sorbent Silasorb-C18, modified by polyvinylpyridinium bromide (PEVP), polydimetyldiallylammonium chloride (PDMDAA), and polyhexamethyleneguanidine chloride (PGMG) were investigated. The limits of detection were 0.1-1 mg/L and 0.01-0.05 mg/L for single and dual-column modes of chromatography, respectively. A comparison of synthesised Silasorb C18-DBSA-PEVP anion-exchanger with several commercial packed materials (Hiks-1, Anieks, TSK gel IC-Anion-PW, TSK gel IC-Anion-SW, BT XI An, Nucleosil 10 SB) was carried out. It is shown that BT I An and BT II An anion-exchangers cannot be used in determining transition metal complexes with EDTA due to high non-ion-exchange sorption of hydrophobic complex anions on the polymer matrix. Silasorb C18-DBSA-PEVP showed the highest selectivity in separating anion complexes of transition metals with EDTA.

Laboratory of Chromatography