First derivative spectrophotometric determination of uranium(VI) and vanadium(V) in natural and saline waters and some synthetic matrices using PAR and cetylpyridinum chloride Original Research Article

A first derivative spectrophotometric method has been developed for the simultaneous determination of uranium(VI) and vanadium(V) using 4-(2′-pyridylazo)resorcinol (PAR) in the presence of cetylpyridinium chloride (CPC) and EDTA. As a result of the addition of CPC, the first derivative spectra of vanadium showed two minima at 575 and 600 nm, the latter being found to be more useful in its determination. Calibration graphs based on first derivative measurements of uranium and vanadium at 563 and 600 nm were found to be linear in the range of 0.4–4.0 and 4.0–16 μg ml−1 with a 3σ detection limit of 0.25 and 3.0 μg ml−1, respectively. The determination of 2 μg ml−1 uranium and 4.0 μg ml−1 vanadium in spiked river water samples gave quantitative recovery and relative standard deviations (n=3) of 0.6 and 0.8%, respectively. The method has been applied to the determination of uranium and vanadium in some synthetic matrices, river and saline water samples.