Sensitivity and selectivity of the reaction of vanadium(V) with 4-(2-Pyridylazo)resorcinol on a solid support containing anion-exchange groups and modified with 8-hydroxyquinoline or 8-hydroxyquinoline-5-sulfonic acid

The effect of the modification of a solid support with 8-hydroxyquinoline (HQ) and 8-hydroxyquinoline-5-sulfonic acid (HQ-SFA) on analytical characteristics of the reaction of vanadium(V) with 4-(2-pyridylazo)resorcinol (PAR) on a solid phase was studied for polyacrylonitrile fiber filled with the AV-17 anion exchanger. Diffuse reflection spectra of the initial and modified supports and of vanadium(V) complexes of PAR on these supports were recorded. It was found that vanadium reacts with PAR on modified supports only in acid solutions. The conditions for the adsorption of vanadium and the dependences of the analytical signal on the acidity of the PAR solution and on the concentration of the modifier on the support were determined. The limits of vanadium detection by the reaction with PAR were calculated (0.5 and 1 ng/mL for AV-17-HQ and AV-17-HQ-SFA, respectively). The selectivity of the reaction of vanadium with PAR on modified supports was estimated with respect to copper, aluminum, iron(III), and zinc. It was found that the modification of the support with HQ and HQ-SFA impairs the analytical characteristics of the reaction of vanadium with PAR on the solid phase and that the use of modified supports for the color reaction of vanadium with PAR is inappropriat