Extraction spectrophotometric determination of vanadium in industrial waste water

A new and simple extraction spectrophotometric method for the determination of vanadium(V) with KIO4, N-phenylbenzohydroxamic acid (PBHA) and crystal violet (CV), in industrial waste water samples is described. It is based on the extraction of mixed-ligand complex V(V)-IO4--PBHA-CV+ into chloroform solution over 2-7 M HCl. The molar absorptivity of the complex is (7.20) x 10(3) 1 mol(-1) cm(-1) at lambda (max) 535 nm. The detection limit of the method is 44 mug l(-1) V. The linearity of the calibration curve is followed up to 6 mug mL(-1) in the organic solution with slope, intercept and correlation coefficient of 1.34 x 10(-1), 6.7 x 10(-3) and + 0.99, respectively. This method enhances the sensitivity of the conventional PBHA method for the determination of vanadium, and is free from interferences of other metal ions commonly associated with vanadium. The method has been successfully tested for the determination of V in the industrial waste water samples.