SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF VANADIUM IN URANIUM RICH HYDROGEOCHEMICAL SAMPLES USING PYRIDYL AZO RESORCINOL (PAR)

A simple and precise method has been developed for the determination of traces of vanadium(V), using 4-(2 pyridyl azo) resorcinol, in natural water samples, containing very high concentrations of uranium. CDTA-pyrophosphate buffer has been used for masking interferants, including uranium which otherwise interferes above 125 ppb. The reaction of vanadium with PAR in the presence of buffer requires a waiting period of 45 min. The Sandell sensitivity of the method is 0.003 mug/ml, at 545 nm at an optimum pH of 6.5 +/- 0.2. The precision of the method is +/- 15% at the 100 pp b level of vanadium(V). The method has been successfully applied to a number of natural water samples during hydrogeochemical exploration.