Automated determination of vanadium(IV) and (V) in natural waters based on chelating resin separation and catalytic detection with Bindschedler’s green leuco base Original Research Article

An automated method for determining V(V) and V(IV) in natural waters has been developed. The method is based on the combination of a selective column extraction using two kinds of chelating resins and an air-segmented continuous flow analysis (ASCFA) using catalytic detection with Bindschedler’s green leuco base (BGL)–KBrO3 system. Based on this method, V(V) in a sample solution at pHs from 2.2 to 3.8 is selectively collected on an acetylacetone-immobilized resin and then V(IV) in the eluent is collected on an 8-quinolinole-immobilized resin separating it from iron species, which interfere with the ASCFA detection. V(V) and V(IV) are successively eluted with diluted hydrochloric acid and the resulting eluent is carried into the ASCFA. The concentrations of vanadium species are determined from the absorbance of BGL. The detection range for vanadium species was 0.05–15.0 nM and the standard deviations at 5.0 nM were 1.1% for V(IV) and 0.9% for V(V), respectively. The method was successfully applied to study the behavior of vanadium species in natural waters.