Separation of chromate and tungstate by reversed-phase high-performance chromatography using rutin as chelating reagent

Abstract

Rutin was used as a chelating reagent to form ternary complexes with metal ions and hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide, CTAB). The retention behaviour of ternary complexes of Cr(VI) and W(VI) on a Nucleosil C 18 column were examined. For chromatographic analysis the sample solution had to be changed because these ternary complexes did not give any peaks in aqueous mediu. A solid-phase extraction step with polyethylene as sorbent and methanol as eluent was introduced. Cr(VI) and W(VI) complexes in methanolic medium gave sharp peaks in the chromatogram and were separated from each other and other metal ions by using a mobile phase of 42.5% (v/v) tetrahydrofuran containing 0.003 M CTAB. The method was applied to the analysis of chromate in geological samples.