Speciation analysis of inorganic vanadium (V(IV)/V(V)) by graphite furnace atomic absorption spectrometry following ion-exchange separation

Abstract

A sensitive and simple method of ion-exchange resin separation and graphite-furnace atomic absorption spectrometry (GFAAS) detection was proposed for the determination of inorganic vanadium species. Methylene Blue (MB) was used as a chelating agent of V(V) for ion-exchange separation. The complex of V(V) and MB could be trapped by ion-exchange resin at pH 3.0 and eluted by 1.0 mol L−1 NaOH. The vanadium species was determined subsequently by GFAAS. The concentration of V(IV) was calculated by subtracting the V(V) concentration from the total concentration of vanadium. Under the optimized experimental conditions, the detection limit of V(V) is 0.48 µg L−1 with RSD of 2.6% (n = 5, c = 2.0 µg L−1). In order to verify the accuracy of the method, a certified reference soil sample was analyzed, and the results obtained were in good agreement with the certified values. The range of recovery for V(IV) and V(V) was 97.8–99.3% and 101.7–103.6%, respectively. The proposed method was applied to the speciation analysis of vanadium in lake-water samples.