Solid-phase extraction for preconcentration and separation of vanadium species in natural waters

For selective preconcentration and separation of vanadium species, several conventional ion-exchange resins, functionalised cellulose sorbents and chelating resins were examined. Cellulose with phosphonic acid exchange groups (Cellex P) was found to be superior for enrichment of both vanadium(IV) and vanadium(V). Both species could be simultaneously eluted using EDTA solution with recoveries of 94-101% and determined by AAS method. An enrichment factor of 150 was obtained. The speciation study of vanadium ions has been tested using CDTA added to the sample or as a selective eluent for V(IV). Application of the proposed method to water analysis is discussed.