Automated determination of vanadium(IV) and (V) in natural waters based onchelating resin separation and catalytic detection with Bindschedler's green leuco base

An automated method for determining V(V) and V(IV) in natural waters has be en developed. The method is based on the combination of a selective column extraction using two kinds of chelating resins and an air-segmented continu ous flow analysis (ASCFA) using catalytic detection with Bindschedler's gre en leuco base (BGL)-KBrO3 system. Based on this method, V(V) in a sample so lution 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-quinoli nole-immobilized resin separating it from iron species, which interfere wit h 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 c oncentrations of vanadium species are determined from the absorbance of BGL . The detection range for vanadium species was 0.05-15.0 nM and the standar d 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 spec ies in natural waters. (C) 2001 Elsevier Science B.V. All rights reserved.