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

A first derivative spectrophotometric method has been developed for the sim ultaneous determination of uranium(VI) and vanadium(V) using 4-(2'-pyridyla zo)resorcinol (PAR) in the presence of cetylpyridinium chloride (CPG) and E DTA. As a result of the addition of CPC, the first derivative spectra of va nadium showed two minima at 575 and 600 nm, the latter being found to be mo re useful in its determination. Calibration graphs based on first derivativ e measurements of uranium and vanadium at 563 and 600 nm were found to be l inear in the range of 0.4-4.0 and 4.0-16 mug ml(-1) with a 3 sigma detectio n limit of 0.25 and 3.0 mug ml(-1), respectively. The determination of 2 mu g ml(-1) uranium and 4.0 mug 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 sa mples. (C) 2001 Elsevier Science B.V. All rights reserved.