Complexation of vanadium(V) with 4-(2-pyridylazo)resorcinol on the solid phase of a fibrous sorbent filled with an anion exchanger

The effect of the order in which the reactants are adsorbed on the rate, se lectivity, and sensitivity of the solid-phase reaction between vanadium and 4-(2-pyridylazo)resorcinol (PAR) has been studied. It is demonstrated that PAR is readily adsorbed on a support filled with the KU-2 cation exchanger but does not react with vanadium. On a support with the AV-17 anion exchan ger, vanadium(V) reacts with PAR irrespective of the order in which vanadiu m and the reagent are adsorbed. The rate of the complexation reaction on th e solid phase depends on the solution acidity. It is found that the complex ation of vanadium with PAR on the solid phase proceeds much more rapidly wh en an acid solution of the reagent is used. It is demonstrated that the rea ction between vanadium and PAR on the solid phase of a fibrous sorbent fill ed with AV-17 significantly outperforms the reaction in solution in sensiti vity (by an order of magnitude) and even greater in selectivity. The detect ion limit of vanadium is 3 ng/mL.